Impacts of Pharmaceutical and Chemical Exposures on Pregnancy in Nigeria and Africa: A Trimester-specific Review

Abstract Pregnancy is a period of heightened vulnerability to toxic exposures, with each trimester representing distinct developmental stages. In Nigeria and across sub-Saharan Africa, pregnant women are commonly exposed to various pharmaceuticals such as antidepressants, antibiotics, contraceptives, antiemetics, vitamins, and antidiabetics, as well as chemicals including alcohol, pesticides, and industrial pollutants like lead and mercury. This narrative review summarizes trimester-specific outcomes and mechanisms of toxicity based on published studies from Nigeria and Africa. Evidence shows that many pregnant women self-medicate or inadvertently consume hazardous substances. About 22.6% of Nigerian women report alcohol use during pregnancy, and nearly 30% self-medicate with drugs such as paracetamol, antimalarials, and antibiotics. First-trimester exposures, when organogenesis occurs, are most strongly linked to structural anomalies like neural tube and cardiac defects, whereas later exposures impair fetal growth and neurodevelopment. Prenatal selective serotonin reuptake inhibitors (particularly paroxetine and fluoxetine) are associated with cardiac and cranial malformations, while antibiotics such as tetracyclines and fluoroquinolones may cause skeletal or cartilage toxicity. Alcohol is a potent teratogen causing fetal alcohol spectrum disorders at any stage. Pesticide exposure in early pregnancy is linked to neural and limb malformations, and lead exposure contributes to miscarriage, preterm birth, low birth weight, and neurodevelopmental deficits. Regional statistics and study data are summarized in tables, with case reports highlighting Nigerian infants affected by fetal alcohol syndrome and lead poisoning. The findings emphasize an urgent need for improved education, regulation, and prenatal screening to reduce these risks in Africa.