A round-up of research on obesity in pregnancy from the ACOG 2017 meeting in San Diego, California.
Effects of obesity on labor Induction
Results from a prospective cohort study presented at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists in San Diego, California, shed new light on the effect of obesity on labor. Researchers from the University of Maryland Medical Center in Baltimore, hypothesized that obesity prolonged induction of labor (IOL), but their findings suggested otherwise.
For the study, the authors enrolled 99 women with singleton pregnancies who were undergoing IOL. Obstetric management was per the provider’s discretion, with IOL via misoprostol, cervical balloon, or intravenous oxytocin. The interval from the start of IOL to latent labor was the primary outcome; the secondary outcome was duration to active labor and delivery. Labor was considered prolonged if greater than 24 hours to latent labor and greater than 36 hours to active labor. Patients were analyzed by body mass index (BMI) <30, 30 to 39.9, and >40. Outcome of the 23 cesarean deliveries were excluded.
Among the 76 women whose deliveries were assessed, median BMI was 36; 17 had BMI <30; 37 had BMI 30 to 39.9; and 22 had BMI >40. Neither parity nor Bishop’s scores were significantly different in any of the BMI groups. Median duration to latent labor, active labor, and to delivery also did not differ (10.6 vs 9.6 vs 12.7 hours; 14.1 vs 15.0 vs 19.2 hours; and 18.5 vs 17.8 vs 20.6 hours). Time to achieve active labor did trend longer with increasing BMI (P = 0.49).
The authors concluded that prospectively analyzed induced labor curves were not significantly different among normal weight, obese, and severely obese women and that, regardless of BMI, IOL is a viable management option.
1. Fitzgerald G. Obesity effect on induction of labor duration. Poster 25R. Presented Tuesday, May 9, 2017 at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists. Obstet Gynecol. 2017;129(5) suppl:189S
Does obesity = worse outcome for women with severe preeclampsia?
Data from a retrospective cohort study challenge the notion that obese women with preeclampsia may have better outcomes than do those who are not obese. The findings were presented at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists (ACOG) in San Diego, California.
Authors from the University of Pennsylvania in Philadelphia, designed the research to look at the rate of adverse maternal outcomes in obese versus non-obese women with severe preeclampsia (PEC-S). All subjects had gestations ≥ 34 weeks and a diagnosis of PEC-S (as defined by ACOG) from 2011 to 2013. Obesity was defined as a body mass index (BMI) ≥ 30. The primary outcome of the study was a composite defined as 1 or more of the following: liver or renal failure, thrombocytopenia, abruption, blood transfusion, pulmonary edema, diffuse intravascular coagulation, stroke, eclampsia, and intensive care unit admission.
Multivariable logistic regression showed that the composite outcome was significantly less likely in women who were obese than in the non-obese women (9.7% vs. 21%, OR 0.40 [0.17-0.93], P = 0.03). The results were unchanged by adjustment for race, mode of delivery, or parity. Obese women were also less likely to have a blood transfusion (P = 0.04) and they had a lower risk of renal failure (P = 0.13). They were more likely to need intravenous antihypertensive medication and be discharged on oral antihypertensive medication than were the non-obese women.
In a press release, the authors said that their findings “suggest that obese women may get a different, less dangerous form of preeclampsia that has a lower risk of complications.” They cautioned, however, that the study does not provide information on the long-term cardiovascular risks associated with a history of preeclampsia.
1. Teefey CP. Adverse maternal outcomes in obese women with severe preeclampsia. Poster 31C. Presented Saturday, May 6, 2017 at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists. Obstet Gynecol. 2017;129(5) suppl:38s
Effects of obesity on cfDNA testing
In women who are obese, cell-free DNA (cfDNA) testing may be more likely to fail, according to results from a retrospective study presented at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists in San Diego, California. The authors caution, however, that a larger study is needed to determine how performance of noninvasive prenatal testing (NIPT) differs in patients who are lean versus obese.
Researchers from the University of South Florida (USF) in Tampa, hypothesized that because obese women have more maternal cfDNA than do women who are lean, “no result” outcomes of testing would be more likely in the former group. Current recommendations for cfDNA testing specify use in women at “high risk” but no guidelines exist for use in special populations such as patients who are obese or “low risk.”
For the study, data on all pregnant women at USF who had NIPT from January 1, 2011 to January 1, 2015 were reviewed. Women with a body mass index (BMI) between 25.0 and 29.9 at initial prenatal visit were excluded. Categorical variables were compared using chi square of Fisher’s exact test, and continuous variables were assessed using a Student t-test.
A total of 277 obese women and 196 women of normal weight were included in the analysis. A “no result” outcome of cfDNA testing was seen in 3.2% of the obese women versus 1.5% of the lean women but the finding did not reach statistical significance (P = 0.24). Mean BMI in the patients with “no result” was 36.2±13.0. One obese woman had a female result on NIPT and male genitalia on ultrasound and the at birth, the infant was found to be 46,XY.
1. Cabrera C. Obesity and cell free DNA testing. 24R. Presented Tuesday, 9, 2017 at the 65th Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists. Obstet Gynecol. 2017;129(5) suppl:189s