In 1999 Haddow et al (NEJM; 1999; 314:549) reported neuropsychological deficits in babies born to inadequately treated hypothyroid mothers. We have compared our management of treated hypothyroidism in 30 pregnancies in 24 mothers delivered before 2000 to 37 pregnancies in 33 mothers since.
TSH levels were measured at booking in 22 (73%) in the pre-2000 group, 6 (27%) of which were raised; and 32 (86%) in the post-2000 group where 12 (38%) were raised. 7 mothers were never seen by the endocrinologist in the pre-2000 group, but all were seen in the post-2000 group. Thyroxine dose was increased in 17 (56.7%) by a mean 58.8+44.5 micrograms thyroxine in the pre-2000; and in 22 (59.9%) by a mean 47.7+31.9 microgram thyroxine. All increases occurred after booking. The number of TSH measurements after booking was mean 3.07 (95% CI: 2.73.5) in the pre-2000 and 3.97 (95%CI: 3.64.3; P<0.001) in the post-2000. TSH levels were measured in the last trimester in 23 (76.7%) in the pre-2000 and 34 (91.9%) in the post-2000 with 2 in each group being raised.
Whilst improvements in overall management have occurred significant numbers are still not having their TSH measurements at booking, and changes in thyroxine therapy are being instituted after booking, and not on confirmation of pregnancy.