Thyroid Function Among Pregnant Women Attending Antenatal Clinic At The Kenyatta National Hospital Principal Investigator

Abstract

Background Maternal thyroid hormone levels are an important determinant of pregnancy and fetal outcomes. Both hyperthyroidism and hypothyroidism have been shown to have adverse maternal and fetal outcomes. There is no data on the magnitude and profile of thyroid dysfunction among pregnant women in Kenya. Objective of the study To determine the prevalence of thyroid dysfunction among pregnant women attending Antenatal Clinic (ANC) at the Kenyatta National Hospital (KNH) and to determine association between thyroid dysfunction in pregnancy to fetal well-being status using a trimester specific obstetric ultrasound. Methods This was a cross- sectional descriptive study. The participants were consenting pregnant women attending ANC aged 18 years and above. One hundred and eight participants were recruited using consecutive sampling. Relevant history and physical examination was carried out using a standard study proforma. Analysis of TSH and FT4 was carried out in the KNH biochemistry laboratory using an automated electro-chemiluminescence immunoassay machine (cobas ® e 6000) and thereafter a trimester specific ultrasound was performed to assess fetal well-being. Results An analysis of the complete data of 107 participants was performed, one participant was excluded due to intrauterine fetal death based on ultrasound. The median age was 29 years. The median gestational age was 32.2 weeks with majority (61.7%) in the third trimester. Only eight (7.5%) participants had previously tested thyroid function while twelve (11.2%) had a family history of goiter. Six out of a hundred and seven participants had thyroid dysfunction giving a prevalence of 5.6% (95% CI 1.9-10.2) with majority (5/6) being diagnosed with subclinical hypothyroidism. Only one participant had overt hypothyroidism and none with either overt or subclinical hyperthyroidism. Only one participant who had reported history of previous pregnancy loss had VII subclinical hypothyroidism. Ten participants who had a history of previous pregnancy loss had normal thyroid function tests. Study directed obstetric ultrasounds were carried out on eighty-four participants (77.8%) among whom eight (7.4%) had abnormal fetal well- being which was classified as being small for dates using trimester specific parameters and one had intra-uterine fetal death (IUFD). There was no significant association (p=0.646) between thyroid dysfunction and markers of fetal well-being. However, the significance of this finding needs further evaluation to determine impact on fetal and maternal outcomes. Conclusion The prevalence of thyroid dysfunction among pregnant women attending ANC was 5.6% with majority (5/6) diagnosed with subclinical hypothyroidism. There were very few study participants with thyroid dysfunction and hence this study was not able to assess any association with markers of fetal well-being.