The purpose of this study is to devise and pilot a BMI-based prenatal vitamin for obese pregnant women. Currently, all pregnant women, regardless of body mass index, take the same prenatal vitamin. The investigators have found that obese pregnant women have higher levels of inflammation and oxidative stress, and a concomitant depletion of specific antioxidant micronutrients. The investigators have also found, in an animal model, that decreasing inflammation and oxidative stress during obese pregnancy was associated with improved offspring outcomes. Here the investigators aim to understand whether a BMI-based prenatal vitamin is effective in decreasing markers of inflammation and oxidative stress by raising concentrations of antioxidant micronutrients and in pregnancies complicated by obesity.

The investigators' central hypothesis is that pregnancy in obese women creates an oxidant/anti-oxidant imbalance, which adversely impacts maternal health and neonatal outcome. The investigators hypothesize that restoring oxidant/anti-oxidant balance with a body mass index (BMI) based prenatal micronutrient supplement will decrease oxidative stress. The investigators aim to devise a prenatal vitamin supplement based on maternal BMI to increase serum levels of antioxidant vitamins in obese pregnancy, to assess how the BMI-based prenatal vitamin supplementation impacts markers of oxidative stress and inflammation in obese pregnant women and to evaluate the effectiveness of this vitamin formulation in reducing oxidative stress and inflammation and improving growth trajectories in infants born to obese women.

The investigators will conduct a double-blind randomized-controlled study. Two groups of women will be randomized independently. 1) Obese women (BMI>30) planning pregnancy through the through advertising and mailings (N=50) and 2) Pregnant women who are early in pregnancy (<13 weeks) will be approached at their first prenatal visit at the BWH and BIDMC obstetric practices (N=120).

Women will be prescreened and approached by study staff if they qualify. After informed consent is obtained, patients will be randomized to either control or intervention group by computer-generated permuted block randomization. All subjects will be given a standard prenatal vitamin provided by the study and in addition, the control group will be given a placebo and the Intervention group will be given a supplement with vitamin C, E, B6 and folate.

The outcomes are maternal systemic markers inflammation and oxidative stress and micronutrients. At the time points mentioned above, the following laboratory assays will be conducted in maternal blood or urine: C reactive protein, vitamins C, E, B6, folate 8-iso-PGF2a and 8-OHdG. The secondary outcomes are cord blood markers of inflammation and oxidative stress, breastfeeding outcomes, and the following infant outcomes over the first year: neurodevelopmental outcome, growth trajectories and adiposity, systemic markers of inflammation and oxidative stress.

Inclusion Criteria:

• Pre-pregnancy weight or early first trimester weight (BMI > or equal to 30 kg/m2)
• Women can be either planning pregnancy (who are trying to conceive or will be trying to conceive in the coming 6 months) or <14 weeks pregnant

Exclusion Criteria:

• More than two first trimester pregnancy losses
• History of delivering an infant with a major congenital anomaly
• Pre-existing diabetes
• Autoimmune disease such as lupus
• Chronic inflammatory condition such as rheumatoid arthritis
• Uncontrolled stage two or three hypertension at baseline (systolic>160 or diastolic>100 mmHg)
• On anticoagulant therapy
• History of cigarette smoking within the past 12 months
• Lactose intolerant
• Vegan
• Unwilling to stop taking their current supplements

Non-PHI, deidentified IPD will be shared with requesting investigators. A limited data set, generated based on variables identified in an analysis plan approved by PNV investigators, will be sent via secure email or shared dropbox to requesting investigators.

Data will be shared after publication of primary outcomes manuscript for a period of ten years.

Investigators requesting access will be asked to submit a proposal and analysis plan to analyze the requested data, including plans for dissemination and authorship.