Obesity During Pregnancy: Prevention of Birth Injuries

Pregnancy obesity is defined as a body mass index (BMI) during pregnancy of 30 or more ( ≥ 30 kg/m2). BMI is based on a mother’s weight relative to her height. Excessive weight gain is typically defined as gaining more than 1.5 pounds per week during pregnancy. Up to 40% of pregnancies are impacted by maternal obesity. Maternal obesity can increase the risk of complications during both pregnancy and labor/delivery. Because of this, mothers who are obese or have excessive weight gain during pregnancy are considered high-risk and should be closely monitored.

Without proper care or management, obesity during pregnancy can cause the following birth injuries (among others):

Pregnancy Weight Gain and BMI Chart- Maternal Obesity and Birth Injury

fetal oxygen deprivation; hypoxia; hypoxic ischemic encephalopathy; birth asphyxiaMaternal Obesity is Linked to Hypoxic-Ischemic Encephalopathy (HIE)

There are a variety of factors that increase a baby’s risk of hypoxic-ischemic encephalopathy, including obesity in the mother. Mothers who are obese or gain excessive weight during their pregnancy increase the risk of both pregnancy complications (such as gestational diabetes and hypertension) and labor and delivery complications (such as labor dysfunction or shoulder dystocia). These factors are all interrelated, and they all translate to an increased risk of birth asphyxia and HIE. This risk can be decreased through proper monitoring and care.

Maternal Obesity is Linked to Cerebral Palsy

Mothers who are overweight or obese have a higher risk of pregnancy or birth-related complications; this translates to a higher risk of hypoxic-ischemic encephalopathy in the baby. HIE is established as a known causative factor in cerebral palsy. Because obesity is a risk factor for underlying HIE, it is also a risk factor for cerebral palsy.

Why Is Maternal Obesity a Risk Factor for Birth Injury?

Obesity is associated with numerous other health conditions such as diabetes and hypertension (high blood pressure) in everyone, not just pregnant women. In pregnancy, obesity and its associated conditions can pose a risk to the baby, necessitating closer monitoring during pregnancy and labor and more frequent follow-up after testing.

Maternal Obesity and the Link to Birth Injury: Diabetes

Maternal Obesity, Gestational Diabetes, and Macrosomia

Mothers who are overweight are more likely to have diabetes, including gestational diabetes, that is detected during the pregnancy itself. The more obese a mother is, the greater her potential risk is for developing diabetes. Medical professionals are required to screen mothers during prenatal care appointments. This is especially important for patients with obesity and diabetes, and even more critical for these patients with the following risk factors:

  • Prior history of gestational diabetes
  • Previous delivery of a macrosomic or LGA (large for gestational age) baby
  • Glucose in the urine
  • Polycystic ovary syndrome (PCOS)
  • Strong family history of diabetes

Maternal Obesity, Gestational Diabetes, and MacrosomiaIf diabetes is not well-controlled, the maternal-fetal membranes may supply the baby with an over-abundance of blood sugar. This causes the baby to grow too big, which is a condition known as macrosomia. Because macrosomic babies are larger than average, they may not be able to fit through the mother’s pelvis. These situations often result in difficult, prolonged labor. With macrosomia, larger babies have a higher risk of getting ‘stuck’ on the mother’s pelvis (shoulder dystocia) due to cephalopelvic disproportion (CPD). Maneuvering techniques to try to get the baby out can cause brachial plexus injuries and Erb’s palsy due to excessive pulling, which can tear the nerve that controls arm movement.

Babies that are very severely stuck might be extracted using instruments like forceps or vacuum extractors, which can increase the risk of a baby having brain bleeds, hypoxic-ischemic encephalopathy, or traumatic brain injury. Babies with CPD can’t be delivered vaginally because they are too big, so the use of assistive devices compounds the risk of traumatic injury while delaying C-section – the safest way to deliver a baby with CPD. Trying to force a vaginal birth can cause trauma to the baby’s head and brain, and birth asphyxia can occur as necessary interventions get delayed.

Macrosomia is a source of much anxiety among health care professionals due to the many risks it poses to the baby. In addition to shoulder dystocia, protracted or arrested labor, operative vaginal delivery, and birth trauma, macrosomia increases the risk of uterine rupture. A ruptured uterus occurs when there is a tear through all layers of the uterine wall. This can cause severe hemorrhaging, which will cause the baby to be severely deprived of oxygen-rich blood. If the tear damages the vessels involved in uteroplacental circulation, that will be a second cause of fetal oxygen deprivation. A uterine rupture requires a prompt emergency C-section to prevent the oxygen deprivation from causing brain damage in the baby.

Maternal Obesity, Gestational Diabetes, and Neonatal Hypoglycemia

Another facet of the link between maternal obesity and birth injury in regards to diabetes involves the baby’s blood sugar after birth. While babies are in utero, they ‘get used’ to a certain level of blood sugar and produce a correspondingly high level of insulin to help them metabolize sugar. When babies are born, they no longer have the high blood sugar supply from the mother the way they did in utero, but may still produce a high level of insulin. When this happens, the baby’s blood sugar can drop dangerously low (neonatal hypoglycemia). This puts the baby’s brain at risk, because brain cells’ source of energy is glucose. Without glucose, cells can begin to die. Babies whose mothers have diabetes may need much closer monitoring and more frequent feeding postnatally to prevent dangerous blood sugar crashes.

What Can Be Done to Reduce the Risk of Diabetes-Related Pregnancy Complications?

Although diabetes is a significant risk factor for birth injuries, proper care and monitoring can help mitigate the risk of birth injury. There are a few things that physicians recommend to help prevent increased risk:

  • Once diagnosed, physicians recommend that mothers test their blood glucose levels at home and keep them within a normal range
  • Frequent check-ups, especially during the last three months of pregnancy
  • Frequent tests to check on the baby’s health, including fetal monitoring, nonstress tests (NSTs), and biophysical profiles (BPPs).
  • Dietary modifications, hypoglycemic medications, or insulin treatments.
  • Planned early delivery, depending on numerous factors. Timing of delivery depends on how well-controlled the diabetes is and whether there are complicating factors like IUGR. Often, delivery occurs between 34-39 weeks.

Maternal Obesity and the Link to Birth Injury: Intrauterine Growth Restriction (IUGR)

Earlier, we discussed how maternal obesity within the context of gestational diabetes can cause a baby to grow too large in the womb (macrosomia). It may sound contrary to intuition, but in other cases, obesity during pregnancy can actually cause the opposite; maternal obesity can result in something known as intrauterine (fetal) growth restriction (or IUGR). If a mother is obese, sometimes the baby may have poor fetal growth and begin to miss weight or length milestones. Small babies are often more fragile and can have reduced oxygen reserves or underdeveloped organs, which means they can’t tolerate the stresses of labor for very long. It’s safest to deliver babies with IUGR by C-section.

Maternal Obesity and the Link to Birth Injury: High Blood Pressure and Preeclampsia

Mothers who are obese may have an increased risk of high blood pressure (hypertension) and preeclampsia (high blood pressure that starts during pregnancy). The volume of blood that passes between mother and baby through the placenta is dependent on many factors, one of which is blood pressure. If the mom’s blood pressure is too high, resistance increases and blood flow to the baby decreases in a condition called reduced uteroplacental perfusion (RUPP). Because the placenta supplies oxygen and other nutrients, hypertension can mean reduced supplies of both to the baby. High blood pressure must be carefully managed and monitored to avoid birth injury and complications for the baby like placental abruption, poor fetal growth, IUGR, and premature birth.

In the case of preeclampsia specifically, high blood pressure becomes even more of a concern, as preeclampsia is a more severe form of hypertension. In preeclampsia, high blood pressure is accompanied by protein in the urine and dysfunction in some major organs. If not properly monitored and cared for, preeclampsia can progress to become eclampsia, which can cause seizures in the mother during pregnancy and labor. This can be life-threatening to both mother and baby. In addition to eclampsia, other complications include:

  • Kidney failure
  • Hypertensive crisis
  • HELLP (Hemolysis, Elevated Liver enzymes, and Low Platelet count) Syndrome

What Can Be Done to Reduce the Risk of Hypertension-Related Pregnancy Complications?

Maternal Obesity and the Link to Birth Injury: High Blood Pressure and PreeclampsiaMothers with obesity and either hypertension or preeclampsia should be very closely monitored by their physicians because they have a high-risk pregnancy. This allows for interventions in case something goes wrong, like if the mother’s condition worsens dramatically or if the baby develops non-reassuring heart tracings, which can be a sign of fetal distress.

In some cases, high blood pressure should be treated with anti-hypertensive medications. For mild to moderate hypertension, the risks of anti-hypertensive medication outweigh the benefits. However, for severe hypertension, the benefits outweigh the risks. Treatment is also recommended in mothers who have symptoms that may be caused by elevated blood pressure (including headache, visual disturbances, and chest discomfort).

  • Normal blood pressure is 120/80 mmHg (Systolic/Diastolic).
  • Medication should be given to mothers with a systolic pressure of 150+ or a diastolic pressure of 100+.
  • Treatment should be given at a lower threshold to younger mothers whose blood pressure is lower or who had a low baseline blood pressure.
  • Target blood pressures:
    • For women with hypertension/preeclampsia: (140-150)/(90-100)
    • For women with end-organ damage: between (140/90) to as low as (120/80).

Anti-hypertensive medications include methyldopa or labetalol, with nifedipine added if needed. In cases of sudden onset (acute) hypertension, IV labetalol or hydralazine should be given.

In many cases, babies whose mothers have preeclampsia are delivered in a planned early delivery to avoid additional health risks to mother and baby. Delivery is timed based on several factors, including:

  • Severity of hypertension/preeclampsia
  • How well-controlled the mother’s blood pressure is
  • Whether there are additional complicating factors such as placental abruption
  • Gestational age of the baby

Situations that require delivery include:

  • Preeclampsia at 37 weeks or later (even if it is non-severe)
  • Evidence of serious maternal end-organ dysfunction, regardless of gestational age
  • Nonreassuring tests of the baby’s well-being, regardless of gestational age

In some cases, hospitals will recommend that mothers have a hospital stay for monitoring if they come in with nonreassuring test results or worsening condition. While hospital stays may be unpleasant, they are often necessary because they allow medical staff to monitor the severity of health conditions and the rate of disease progression.

In some cases of nonsevere preeclampsia, some mothers may choose outpatient monitoring. Medical staff should provide maternal and fetal evaluations once every 1-3 days, and provide mothers with access to medical care and a labor and delivery unit if the need arises. Mothers should be informed by their doctors of the signs and symptoms of major blood pressure changes and preeclampsia, and have an explanation of how to monitor their baby’s movements. Mothers can then monitor their health and report to their physician if their health or their baby’s movements change. Mothers should also be told to call the physician immediately if they have:

  • Severe or persistent headache
  • Visual changes
  • Shortness of breath
  • Pain in the upper abdomen (epigastric pain)

Mothers should also seek medical treatment at their hospital if:

  • There is decreased movement of the baby
  • Vaginal bleeding
  • Abdominal pain
  • Rupture of the membranes
  • Uterine contractions

Obesity and the Link to Birth Injury: Twin Pregnancies

Obese pregnant women are at a higher risk of having dizygotic (but not monozygotic) twins. Twin pregnancies increase the babies’ risks of experiencing complications like:

Twin pregnancies require more frequent monitoring and prenatal testing, which includes thorough assessment of the babies’ growth. PROM (premature rupture of the membranes) can cause preterm birth, which can cause a baby to get an infection. Scheduled early delivery of twins can help prevent babies from having injury caused by complications such as PROM. Furthermore, if one or both of the babies isn’t getting enough oxygen and nutrients, an early delivery is required in order to prevent brain damage.

If PROM occurs or there is any reason to suspect maternal infection and/or chorioamnionitis at or near the time of delivery, IV antibiotics must be given to the mother. The antibiotics will transfer to the babies and help protect them from infection. The babies may need antibiotics after birth as well, and antibiotics should be given prophylactically in situations where there is suspicion of infection.

Dizygotic twins must usually be delivered at or before 38 weeks. If additional complicating factors are present (such as preeclampsia or IUGR), the babies will usually need to be delivered earlier.

Obesity and the Link to Birth Injury: Urinary Tract Infections (UTIs)

Maternal obesity is correlated with urinary tract infections (UTIs). Women who are overweight before pregnancy have a 42% increased risk of UTI. A UTI increases the risk of preterm birth and low birth weight, and both complications are very dangerous for a baby.

At the first prenatal visit, it is the standard of care for medical professionals to get a urine culture to check for UTIs. The urine culture should be tested for specificity (antibiotic susceptibility) so the correct antibiotic is prescribed. UTIs can safely be treated during pregnancy with antibiotics (but not with fluoroquinolones or tetracyclines).

The mother must be re-tested after treatment to make sure the antibiotic worked. Since there is a high rate of UTI recurrence, the mother should be tested again during the third trimester. Any time the mother has symptoms of a UTI, she should be promptly tested.

Quick and proper treatment of UTIs can prevent preterm birth as well as an infection that travels to the baby at birth. Infections caused by an improperly-treated UTI can cause a newborn to have sepsis, septic shock, meningitis and permanent brain damage.

If a UTI is present at the time of delivery, IV antibiotics should be given to the mother to prevent passing the infection to the baby.

Obesity and the Link to Birth Injury: Vaginal Birth After Delivery (VBACs)

Obese mothers who have a trial of labor after having one or more prior C-sections are less likely to be successful than mothers with normal BMI. In the largest prospective multicenter study, the rate of failed trial of labor increased from 15% in normal-weight mothers to 30% in obese mothers to 39% in severely obese mothers, with the rate of uterine rupture increasing with maternal weight. If a labor induction drug such as Pitocin is used, the mother’s risk of uterine rupture is even greater. In addition, the risk of uterine rupture increases with each C-section delivery a mother had. Physicians must thoroughly explain all these risks to their patients.

Every delivery unit must have the capability to promptly perform an emergency C-section if needed, and this is especially important for obese mothers attempting a VBAC. A ruptured uterus is life-threatening for both the mother and baby and when it occurs, the baby must be quickly delivered by C-section.

Obesity and the Link to Birth Injury: Anesthesia Complications

Compared to mothers within the normal weight range, obese mothers have a higher rate of the following:

  • Failed labor anesthesia and analgesia
  • Difficult breathing tube placement (intubation)
  • Low blood pressure (hypotension)
  • Fetal heart rate decelerations (nonreassuring heart tracings)

Maternal complications associated with analgesia/anesthesia can delay a necessary C-section. Delays in C-sections prolong fetal distress. Physicians must be aware of these potential complications in their obese patients and must take steps to prevent them.

Obese mothers should be evaluated by an anesthesiologist before or early in labor so the medical team is more prepared for intubation, anesthesia administration, and other procedures related to C-section. Early placement of epidural or intrathecal catheters may prevent the need for general anesthesia later if emergency C-section is needed.

Every effort must be made to prevent the mother from having hypotension, which can occur if anesthesia is not properly given and/or the mother is not properly monitored. Hypotension can cause a decreased flow of blood to the baby, which can cause oxygen deprivation and hypoxic-ischemic encephalopathy (HIE) in the baby.

Maternal Obesity and the Link to Birth Injury: Prolonged Labor, Dysfunctional Labor, and Associated Complications

Labor is known to progress in a certain approximate pattern, but this pattern can be changed by numerous factors, including a mother’s weight. Mothers with a high BMI tend to have a longer first stage of labor, which is associated with an increased risk of prolonged or arrested labor.

C-section | Maternal Obesity and the Link to Birth Injury: Prolonged Labor, Dysfunctional Labor and Associated ComplicationsWomen who are obese are more likely to have a dysfunction of labor. If there is a dysfunction of labor, a C-section may be necessary. This is why physicians must ensure that obese mothers have their labor and delivery at a medical facility that has the capacity to do an emergency C-section if necessary.

During labor, the medical team must properly assess the mother so they can diagnose prolonged or arrested labor if it occurs. This is done in several ways, but one of the most important components is serial cervical examinations, which can tell how far the cervix is opening during active labor.

Prolonged Labor and Labor Induction Drugs (Pitocin/Oxytocin and Cytotec)

Labor is a physically-taxing process that can cause trauma – the longer the labor, the greater the risk of birth asphyxia and trauma to the baby. Sometimes, to speed up the labor process during the active phase of the first stage of labor, medical staff will give mother Pitocin (a synthetic version of the hormone oxytocin) or Cytotec. These drugs make labor contractions stronger, but the effects of these drugs are unpredictable: the same dose in one mother may have no effect, while in another it may cause uterine hyperstimulation, making contractions too frequent, long, and intense. This causes:

  • Tachysystole (too-frequent and potentially over-forceful contractions – 6+ contractions over a 10-minute period), and
  • Hypertonic uterus (a uterus that has a single contraction lasting more than 2 minutes).

These conditions mean that the mother’s uterus doesn’t have time to fully relax between contractions. Usually, the baby gets oxygen during relaxation periods. However, if the uterus is hyperstimulated, the baby doesn’t get enough oxygen due to tachysystole and hypertonicity. When this happens, oxygen deprivation starts to impact the baby’s heart rate, showing non-reassuring fetal heart rate tracings (a sign of fetal distress) on the fetal heart rate monitor. As this continues, the baby can get progressively more oxygen-deprived, which can cause brain damage if improperly handled. If hyperstimulation occurs, the baby must be delivered quickly via emergency C-section to prevent permanent injury.

Because of the potential risks of using labor induction drugs, it is very important that mothers give informed consent – the doctor must explain all the risks and benefits of using the drugs, as well as any alternatives, and the mother must agree to the drugs or any procedures understanding the relative risks and benefits.

It is important to note that obese women are more likely to need contractions augmented with drugs like Pitocin, and that these drugs are also more likely to fail to induce labor in obese women, which means that they are more likely to require a C-section.

Prolonged Labor and Infection

Chorioamnionitis and Maternal ObesityObese mothers are more likely to have a prolonged first stage of labor. Women with a prolonged first stage of labor have higher odds of chorioamnionitis (an infection of the membranes surrounding the baby). In situations where chorioamnionitis is suspected, mothers should be given IV antibiotics (such as ampicillin or penicillin and gentamycin). If antibiotics are not given, when the membranes rupture, the baby is exposed to the bacteria that caused the infection, which could lead to brain damage from sepsis or meningitis. In addition, the baby should get a single dose via IV after birth. In some cases of chorioamnionitis, C-section may be required because the chorioamnionitis may cause a failure to progress through the birth canal.

Maternal Obesity and Fetal Heart Rate Monitoring During Labor

Fetal heart rate monitoring is a critical component of assessing a baby’s health in utero. While a mother is in labor, physicians should be assessing the baby’s well being with a fetal heart rate monitor. In many cases, doctors use external monitors, but it’s important to note that individuals who are overweight or obese may have accumulations of soft tissue that can make external monitoring more difficult. It is important to ensure that the monitor is accurately picking up the fetal heart rate tracings to know if the baby is tolerating labor well. If possible, an internal fetal monitor should be used for monitoring the baby when mothers are obese.

Labor monitoring with an external monitor, intrauterine pressure catheter, pulse oximeter and fetal scalp monitor

Monitoring the baby’s heart rate is critical during labor

Maternal Obesity: Ensuring a Healthy Pregnancy and Delivery

Obesity is a major risk factor for birth injury, and it’s critical that medical professionals treat it as such. Mothers and their babies must receive care that addresses their unique needs throughout pregnancy, labor, and delivery. This includes:

  • Proper monitoring throughout pregnancy
  • Proper treatment of underlying medical issues
  • Continual assessment of the baby’s growth and well-being

One of the critical components of ensuring the baby and mother’s health during a pregnancy if there is obesity, hypertension, or diabetes is antenatal testing. During pregnancy, medical staff should be conducting numerous tests to ensure that both the mother and baby are progressing through the pregnancy as expected. Tests included as part of this monitoring should include:

  • Non-stress tests (NSTs) to record the baby’s vigor, movement, and heartbeat, using an electronic fetal monitor and fetal ultrasound
  • Biophysical profiles (BPPs), which measure the baby’s rate, muscle tone, movement, breathing, and the amount of amniotic fluid around the baby, often in conjunction with an NST
  • Amniotic fluid index (AFIs) to see how much amniotic fluid surrounds your baby; these are often provided as part of a BPP
  • Doppler flow monitoring to test whether the baby is getting adequate blood flow to the brain, organs, and extremities

In many cases, early scheduled C-section is indicated when a mother’s due date nears or if testing shows abnormalities. If obese and overweight mothers are attempting vaginal delivery, the delivery unit must have the capacity to perform an emergency C-section if it becomes necessary.

Call the Trusted Birth Injury Attorneys at Reiter & Walsh ABC Law Centers

The birth injury attorneys at Reiter & Walsh ABC Law Centers focus solely on birth injury, and can help you and your child if they were injured as a result of poor care during pregnancy, labor, or delivery. Medical professionals must provide care that is up to the ‘standards of care’ – if your doctor did not provide proper care for you and your child while you had obesity during pregnancy, feel free to call us for a free consultation. Our birth injury attorneys are compassionate, driven, and already ready to speak with you. Your information is always 100% confidential, and you will never pay fees out-of-pocket.

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Video: Neonatal Hypoglycemia and Maternal Obesity

Related Reading:


  • Torloni MR, Betrán AP, Horta BL, et al. Prepregnancy BMI and the riskof gestational diabetes: a systematic review of the literature with meta-analysis. Obes Rev 2009; 10:194.-Scott-Pillai R, Spence D, Cardwell CR, et al. The impact of body mass index on maternal and neonatal outcomes: a retrospective study in a UK obstetric population, 2004-2011. BJOG 2013; 120:932.
  • Blomberg M. Maternal obesity, mode of delivery, and neonatal outcome. Obstet Gynecol 2013; 122:50.
  • Gunatilake RP, Perlow JH. Obesity and pregnancy: clinical management of the obese gravida. Am J Obstet Gynecol 2011; 204:106.
  • American College of Obstetricians and Gynecologists. ACOG Committee opinion no. 549: obesity in pregnancy. Obstet Gynecol 2013; 121:213.
  • Owens LA, O’Sullivan EP, Kirwan B, et al. ATLANTIC DIP: the impact of obesity on pregnancy outcome in glucose-tolerant women. Diabetes Care 2010; 33:577.
  • Ramsay JE, Ferrell WR, Crawford L, et al. Maternal obesity is associated with dysregulation of metabolic, vascular, and inflammatory pathways. J Clin Endocrinol Metab 2002; 87:4231.
  • Hauth JC, Clifton RG, Roberts JM, et al. Maternal insulin resistance and preeclampsia. Am J Obstet Gynecol 2011; 204:327.e1.
  • Roberts JM, Bodnar LM, Patrick TE, Powers RW. The Role of Obesity in Preeclampsia. Pregnancy Hypertens 2011; 1:6.
  • Marshall NE, Guild C, Cheng YW, et al. Maternal superobesity andperinatal outcomes. Am J Obstet Gynecol 2012; 206:417.e1.
  • Reynolds RM, Allan KM, Raja EA, et al. Maternal obesity during pregnancy and premature mortality from cardiovascular event in adult offspring: follow-up of 1 323 275 person years. BMJ 2013; 347:f4539.