BMI‐based Prenatal Vitamins in Obese Pregnancy: Cohort Profile
Authors: Sen Sarbattama , Penfield‐Cyr Annie , Benjamin Charis , Tynan Monica , Herlihy Mary , Hacker Michele , McElrath Thomas 
Published: November 2023

Background

In the United States, one in three women is obese before pregnancy. Obesity is associated with inflammation and oxidative stress, which has been implicated in fetal programming of obesity.

Objective

The Prenatal Vitamin (PNV) Study is a randomized controlled trial of a BMI‐based prenatal vitamin, formulated to have higher concentrations of vitamins C, E, B6, and folic acid, compared to a standard prenatal vitamin in obese pregnant women. We have previously found that obese pregnant women have lower concentrations of these antioxidant micronutrients, and higher inflammation and oxidative stress compared to lean pregnant women. The overall objective of the PNV study is to determine whether providing a BMI‐based supplement to obese pregnant women will decrease markers of inflammation and oxidative stress. Here we report the baseline demographics and perinatal outcomes for 130 subjects enrolled in this study.

Methods

Obese pregnant women (BMI≥30kg/m2) were recruited between 2014 and 2016 in Boston, MA. Exclusion criteria included women with a gestational age >13 weeks at the time of consent, plans to move from the immediate area within one year of birth and pre‐existing diabetes, autoimmune disease or stage two or three hypertension. We collected information from mothers using questionnaires and obtained clinical information from their medical record.

Results

From the 113 eligible women, 4 pregnancies ended in miscarriages and 68 women have delivered live births to date. The mean BMI of the cohort was 35.6kg/m2. Subjects were similar to the Massachusetts population in terms of age at pregnancy, level of education and racial composition. 60% of women delivered by vaginal delivery, the mean gestational age of infants was 37.7 weeks, with 23% of infants born ≤37 weeks. Mean birth weight was 3.14kg. Interestingly, 81% of subjects planned to exclusively breastfeed at delivery, but only 60% were exclusively breastfeeding at hospital discharge.

Conclusions

The overall demographics of this cohort of obese women were similar to the population of Boston. The perinatal characteristics suggest that women were more likely to deliver preterm and have a cesarean section delivery than the overall population. Breastfeeding initiation and early continuation are strikingly lower than the overall population, despite high rates of intention to exclusively breastfeed.

Support or Funding Information

This study was supported by a K23 grant from the NIH (ref. no. K23HD074648) and The Charles H. Hood Pediatric Research Grant

Characteristics of PNV Study Cohort

Maternal Characteristics
N=113

Age at Enrollment (years): mean(SD)
30.7 (5.7)

BMI at Enrollment (m2/kg): mean(SD)
35.6 (5.5)

Gestational Age at Enrollment (weeks): mean(SD)
10.2 (2.0)

Parity: n(%)

1
7 (6)

2
19 (17)

3
28 (25)

>3
59 (52)

Ethnicity: n(%)

Hispanic
47 (42)

Race: n(%)

Asian
2 (2)

Hawaiian or Pacific Islander
1 (1)

Black or African American
31 (27)

White or Caucasian
48 (43)

More than One Race
9 (8)

Unknown/Not Reported
22 (19)

Marital Status: n(%)

Single
38 (34)

Married
57 (50)

Other
18 (16)

Education: n(%)

Some High School
4 (4)

High School Diploma/No Bachelor's Degree
24 (22)

Some College/Bachelor's Degree/Professional Degree
81 (74)

Household Income: n(%)

<$20,000
30 (29)

$20,000–$50,000
35 (34)

$50,000–$70,000
12 (11)

$70,000–$100,000
5 (5)

>$100,000
22 (21)

Insurance (private=yes): n(%)

Yes
54 (48)

Perinatal Outcomes
N=68

Gestational Age at Delivery (weeks): mean (SD)
37.7 (3.0)

Mode of Delivery: n (%)

Vaginal
38 (62)

Infant Birth Weight (kilograms): mean (SD)
3.15 (0.7)

Infant Birth Length (centimeters): mean (SD)
48.3 (5.7)

Intention to Exclusively Breastfeed: n (%)

Yes
52 (81)

Exclusively Breastfeeding at Hospital Discharge: n (%)

Yes
37 (60)