Do vitamins and natural supplements improve pregnancy rates?

Abstract

Maternal and perinatal outcomes of assisted reproductive technology (ART) can be improved greatly by adoption of optimal nutritional and lifestyle practices for both males and females. Lifestyle practices potentially associated with adverse perinatal outcomes include being underweight or overweight, smoking, excessive alcohol or caffeine intake, excessive exercise, inadequate micronutrient intake, and increased psychological stress. Additional nutritional factors with potential effects on pregnancy or birth outcomes include folate (neural tube defects [NTD], reduced sperm count), iodine (infant cognitive development, pregnancy loss), zinc (pregnancy complications, pre-eclampsia, growth retardation, congenital abnormalities, impaired sperm maturation), vitamin D and/or calcium intake, magnesium, selenium, copper and calcium (pre-term delivery, pre-eclampsia or abnormalities in fetal development), and iron (intrauterine growth restriction and anaemia). There is also increasing interest in the effects of natural therapies on perinatal and obstetric outcomes. Of these, maternal vitamin, mineral or natural therapy supplementation prior to ART may potentially improve ART outcomes and pregnancy rates. Issues to consider include which are the most important micronutrients to supplement with and the efficacy, safety, and cost-effectiveness of single micronutrient supplementation compared to supplementation with combined multivitamins and natural therapies. Nutritional interventions pre or during pregnancy should aim to optimize the health of both the mother and the baby. The clinical endpoints of interest include both pregnancy rates and adverse perinatal and obstetric pregnancy outcomes such as low birth weight, preterm birth, miscarriage, congenital abnormalities, and pre-eclampsia. Assisted reproductive techniques may be associated with a low birth weight and a higher risk of multiple gestation, and multiple gestation is associated with adverse obstetric and perinatal outcomes such as pregnancy complications, hypertension, and pre-eclampsia, low birth weight, and intrauterine growth retardation, pre-term birth or miscarriage, and deleterious long-term health. The literature on improving these outcomes in non-ART births is therefore relevant to assess.