Practice Essentials
Results from the 2017-2018 National Health and Nutrition Examination Survey indicate that an estimated 31.1% of US adults aged 20 years and older are overweight (body mass index [BMI] of 25.0-29.9 kg/m2) and 42.5% have obesity (BMI, greater than or equal to 30.0 kg/m2), including 9.0% who have severe obesity (BMI, greater than or equal to 40.0 kg/m2). Among women, many of whom are of reproductive age, 26.9% are overweight, 42.1% have obesity, and 12.0% have severe obesity. The prevalence of obesity has been steadily rising in the United States. [1]
Preliminary data show that undesired weight gain has increased during the COVID-19 pandemic. These data include 36 states with an obesity prevalence of over 30%, with 16 states that have a prevalence of over 35%. Rising obesity rates are one of the social determinants of health. Among women, the prevalence of obesity is 56.7% among Black women, 43.7% among Hispanic women, and 39.8% among White women. [2]
A pregnancy-specific definition of obesity has not been standardized; thus, pregnant patients are often considered obese or non-obese based on their pre-pregnancy BMI, or the BMI at the initial prenatal visit if this is unknown. Many factors contribute to the development of obesity, with lifestyle and diet being the most important. Owing to increasing prevalence, obstetric care providers will need to be well versed in the care of the pregnant patient with obesity.
Tables
Antepartum Care |
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Initial obstetrics visit |
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BMI of < 40 kg/m2 |
BMI of ≥40 kg/m2 |
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History and physical examination screening for maternal comorbidities |
Consider maternal echocardiogram, pulmonary function testing, sleep study |
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Laboratory testing |
+/- Thyroid function tests |
Thyroid function tests |
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A1c if not diabetic [24] |
A1c if not diabetic, with GTT as indicated [24] |
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| +/- Hypertension panel for baseline | Hypertension panel for baseline | ||
Ultrasound scan |
First trimester dating/rule out multiples |
First trimester dating/rule out multiples |
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Counseling on weight gain |
11-20 lb total |
< 15 lb and none is acceptable in the setting of excellent nutrition |
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Exercise |
Aerobic activity minimizing high impact |
Walking and swimming (likely best tolerated) |
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Genetic counseling/screening |
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Aneuploidy – no different |
Serum analytes OK |
Serum analytes OK |
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NT can be difficult [13] |
NT very challenging [13] |
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NIPS – may have test failure more commonly |
NIPS may not perform well, especially early |
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Patient counseling regarding screening |
Test performance similar to that in non-obese patients |
Testing performance is compromised by obesity, and this is “dose” based |
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Prenatal care through 24 weeks' gestation |
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Ultrasound scan |
Detailed anatomy scan at 20 weeks |
Detailed anatomy scan at 20 weeks |
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Possible fetal echocardiogram at 24 weeks [16] |
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Weight |
Closely monitor and counsel patient |
Closely monitor and counsel patient |
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Prenatal care at 24-36 weeks' gestation |
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Laboratory testing |
1 hour 50 g Glucola challenge/Hct |
1 hour 50 g Glucola challenge/Hct |
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| Consider hypertension screening for baseline if not already done | |||
Ultrasound scans |
Serially for growth q 4-6 weeks until delivery |
Serially for growth q 3-4 weeks until delivery |
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Frequency of visits for screening (development of complications will require more frequent visits) |
Q 4 weeks until 28-32 weeks, then q 2 weeks until 36 weeks, then q 1-2 weeks until delivery |
Q 4 weeks until 28 weeks, then q 1-2 weeks until 36 weeks, then weekly |
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Weight gain |
Closely monitor and counsel patient |
Closely monitor and counsel patient |
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Antenatal surveillance (NST/AFI) |
For BMI of 35.0-39.9 kg/m2, consider weekly antenatal testing starting at 37 weeks’ gestation |
Consider weekly antenatal testing at 34 weeks |
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Anesthesiology |
Consider anesthesia consult if comorbidities such as OSA are present | Consider anesthesia consult Evaluate labor and delivery unit to see if they have the equipment and staff to handle patient’s size |
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TOLAC counseling |
Per routine for non-obese patients |
Factor in lower success rate with elevated BMI |
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Prenatal care at ≥36 weeks' gestation |
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Antenatal surveillance |
FKC and other only as indicated for non-obese patients if BMI < 35.0 For patients with BMI of 35.0-39.9, consider weekly antenatal testing starting at 37 weeks’ gestation |
Potentially reconsider NST/AFI starting at 36 weeks if not started earlier |
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| Discussion of delivery plan | Per routine for non-obese patients | Consider induction of labor at 39 weeks, if not already delivered Discuss activities to expect if cesarean section needed |
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Delivery/Intrapartum Care |
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Timing of delivery |
By 41.0 weeks but 40 weeks reasonable and even 39 weeks if excellent Bishop score [33] |
Some experts recommend delivery at 39 weeks if not already delivered for comorbidities [33] |
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Anesthesiology |
Consult as indicated for non-obese patients |
Alert them for anesthesia assessment when patient admitted even if not anticipating need for anesthesia services Can assess if regional anesthesia is an option or not |
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Unscheduled cesarean section for indications |
Routine management [39] |
Consider in labor management given the inability to do a truly emergent cesarean section [39] |
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Incision type for cesarean section |
Routine management [19] |
Consider patient body habitus; consider supra-umbilical if large pannus Vertical incision seems to have fewer complications |
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Antibiotic coverage for cesarean section |
Routine management [44] |
Consider increased dose based on weight and consider repeat dose 4 hours post initial dose [44] |
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Postpartum Care |
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DVT prevention |
Similar to non-obese patients [49] |
Consider use of anticoagulation medications, especially if patient has other risk factors for DVT, such as cesarean section, preeclampsia, infection [49] Weight based rather than BMI based is preferred |
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Difficulty with lactation |
Lactation consultation in hospital and after discharge [51] |
Lactation consultation in hospital and after discharge [51] |
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| AFI = amniotic fluid index; BMI = body mass index; DVT = deep vein thrombosis; FKC = fetal kidney circumference; GTT = glucose tolerance test; Hct = hematocrit; NIPS = noninvasive prenatal screening; NST = nonstress test; NT = nuchal translucency; OSA = obstructive sleep apnea; TOLAC = trial of labor after a cesarean section. | |||
