Ultrasonographically determined thyroid volume in pregnant Nigerian women

Abstract

We determined the normal thyroid volume in Nigerian pregnant women using ultrasound at Nigeria's largest hospital. A group of 211 nongoitrous healthy pregnant women from the three major Nigerian tribes and five of the six geopolitical zones were studied. The mean age of subjects was 31.14 years ± 3.97 years. Patients in their second and third trimester were 122 (56.4%) and 74 (34.1%) respectively. The parity of the patients ranged from 0 to 5, with 86.2% having a parity of 3 or less. The combined thyroid volume ranged from 5.1 to 33.3cm3 with mean volume of 15.8cm3± 4.9cm3. The right and left lobes had mean volumes of 8.3cm3 ± 2.8cm3 and 7.5cm3± 2.5cm3 respectively. Greater than four-fifth of the patients (85.7%) had a thyroid volume less than 21 cm3. There was a weak correlation between the thyroid volume and parity (r =0.212, p= 0.002), but no correlation with gestational age (r=0.122, p=0.082), multiple pregnancy (p =0.715) or maternal age (p=0.193). The values obtained in our study are similar to those from previous studies among Caucasians and in agreement with the argument of the cumulative goitrogenic effect of successive pregnancies.