History
Preconception
Weight loss before pregnancy, whether achieved via surgical or nonsurgical methods, has been shown to be the most effective intervention to improve medical comorbidities, especially diabetes and hypertension. Obese women who have even small weight reductions before pregnancy may have improved pregnancy outcomes if they can avoid excessive weight gain once pregnant. [2, 3] Unfortunately, many women present for obstetrical care with an elevated BMI.
It is recommended that women with a history of bariatric surgery wait 12-24 months before conceiving so that the fetus is not exposed to a rapid maternal weight loss environment and so that the patient can achieve full weight loss goals. Unfortunately, pregnancy may occur prior to this recommended time frame. The number of bariatric surgical procedures performed annually has dramatically increased, with many performed in reproductive-aged women. [3] Obstetric care providers can expect to manage increasing numbers of pregnancies in women with a history of bariatric surgery. (Refer to Medscape article on bariatric surgery for additional information).
Physical Examination
Calculating BMI and Weight Gain Counseling
A full history and physical exam is completed at the new obstetrics visit. A woman’s BMI is calculated at the initial visit. Obesity class I is defined as BMI 30 to 34.9 kg/m2, obesity class II as BMI of 35 to 39.9 kg/m2, and obesity class 3 as BMI greater than or equal to 40 kg/m2. This BMI is used to provide counseling guided by Institute of Medicine (IOM) recommendations for gestational weight gain during pregnancy. The IOM guidelines recommend a total weight gain of 15-25 lbs. for overweight women and 11-20 lbs. for obese women. [4] These recommendations have some limitations. As mentioned earlier, a pregnancy-specific definition of obesity has not been standardized so we typically use pre-pregnancy BMI. BMI is imperfect as it does not tell the whole story about the composition of someone’s body. One also needs to realize that weight gain is used simply as a proxy measure for the nutritional status of the woman. It is the actual nutritional quality of food intake that is critical and not simply the act of gaining weight. Women tend to gain the amount of weight they feel that they should. Unfortunately, obese women expect that a weight exceeding IOM recommendations is appropriate and in turn gain in excess of the recommendations. [5] Women’s nutritional status before and during early pregnancy may play an important role in ensuring successful pregnancy outcomes. Preconceptional and periconceptional intake of vitamin and mineral supplements is associated with reduced risk of low birthweight and/or small-for-gestational age infants and preterm deliveries. [6] Though inadequate weight gain and weight loss have been associated with small-for-gestational age and even decreased lean body mass in the neonate, some studies have shown that in the morbidly obese (BMI >40) woman weight gain lower than 10 pounds and even weight loss in the setting of good balanced meals with appropriate caloric and nutritional intake may be acceptable. [7] Careful evaluation of the woman’s diet are key in this situation.
Increased Maternal and Fetal Risks
Obese pregnant women are at increased risk for many maternal and perinatal complications, and the risks are amplified with increasing degrees of maternal obesity. For this reason, a detailed history and physical examination are critical at the initial obstetrics visit with ongoing monitoring as needed.
Tables
Antepartum Care |
|||
Initial OB visit |
|||
< 40 BMI |
BMI 40+ |
||
H&P screening for maternal co-morbidities |
Consider maternal echocardiogram, pulmonary function testing, sleep study |
||
Laboratory testing |
+/- Thyroid function tests |
Thyroid function tests |
|
A1c if not diabetic [20] |
A1c if not diabetic with GTT as indicated [20] |
||
U/S |
First trimester dating/rule out multiples |
First trimester dating/rule out multiples |
|
Counsel on weight gain |
11-20 lbs. total |
< 15 lbs. and none is acceptable in the setting of excellent nutrition |
|
Exercise |
Aerobic activity minimizing high impact |
Walking and swimming (likely best tolerated) |
|
Genetic Counseling/Screening |
|||
Aneuploidy – no different |
Serum analytes OK |
Serum analytes OK |
|
|
NT can be difficult [12] |
NT very challenging [12] |
|
NIPS – may have test failure more commonly |
NIPS may not perform well especially early |
||
Patient counseling regarding screening |
Test performance similar to non-obese patients |
Testing performance is compromised by obesity and this is “dose” based |
|
Prenatal Care through 24 weeks gestation |
|||
Ultrasound |
Detailed anatomy scan at 20 wks |
Detailed anatomy scan at 20 wks |
|
Possible fetal echo at 24 wks [15] |
|||
Weight |
Closely monitor and counsel patient |
Closely monitor and counsel patient |
|
Prenatal Care 24 – 36 weeks gestation |
|||
Labs |
1 hr 50 gm glucola challenge / Hct |
1 hr 50 gm glucola challenge/Hct |
|
Ultrasounds |
Serially for growth q 4-8 wks until delivery |
Serially for growth q 3-4 wks until delivery |
|
Frequency of visits for screening – (development of complications will require more frequent visits) |
Q 4 wks until 28-32 wks then q 2 wks until 36 wks then q 1-2 wks until delivery |
Q 4 wks until 28 wks then q 1-2 wks until 36 wks then weekly |
|
Weight gain |
Closely monitor and counsel patient |
Closely monitor and counsel patient |
|
Antenatal surveillance (NST / AFI) |
Only as done for non-obese patients |
Potentially start at 32 wks in super morbid obesity (BMI 50+) |
|
Anesthesiology |
Consider anesthesia consult, Evaluate L&D unit to see if they have the equipment to handle patient’s size |
||
TOLAC counseling |
Per routine for non-obese patients |
Factor in lower success rate with elevated BMI |
|
Prenatal Care 36+ weeks |
|||
Antenatal surveillance |
FKC and other only as indicated for non-obese patients |
Potentially consider NSTs/AFI starting at 34-36 wks if not started sooner due to complications |
|
Delivery /Intrapartum Care |
|||
Timing of delivery |
By 41.0 wks but 40 wks reasonable and even 39 wks if excellent Bishop score [30] |
Some experts recommend delivery at 39 wks if not already delivered for co-morbidities [30] |
|
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 |
|
Unscheduled cesarean section for indications |
Routine management [35] |
Consider in labor management given the inability to do a truly emergent cesarean section [35] |
|
Incision type for cesarean section |
Routine management [17] |
Consider patient body habitus |
|
Antibiotic coverage for cesarean section |
Routine management [40] |
Consider increased dose based on weight and consider repeat dose 4 hours post initial dose [40] |
|
Postpartum Care |
|||
DVT prevention |
Similar to non-obese patients [45] |
Consider use of anticoagulation meds especially if other risk factors for DVT such as cesarean section, preeclampsia, infection, etc. [45] |
|
Difficulty with lactation |
Lactation consultation in hospital and after discharge [47] |
Lactation consultation in hospital and after discharge [47] |
|
