Healthy pregnant women who are in their first or second trimester and who intend to breastfeed after delivery will be eligible to participate in this study.Women with any of the following conditions will be excluded: pregnancy beyond the second trimester, chronic medical condition, abnormal fetal screen (ultra-sound/blood/amniocentesis), not intending to breastfeed, not living in Lebanon for at least six months after delivery, twin gestation, and preterm birth (at