Hyper- or hypothyroidism is closely related to the reproductive system, and pregnancy can be adversely affected by hyperthyroidism.
I: Effects of hyperthyroidism on maternity
After pregnancy, influenced by placental hormones in the body, pregnant women are in a relatively active state of the thyroid gland during pregnancy. The volume of the thyroid gland in pregnant women increases by 30% to 40% compared to non-pregnancy. Improper control of hyperthyroidism can have serious effects on women and children: 1) cause miscarriage, premature birth and fetal growth restriction; 2) cause maternal hyperthyroidism crisis; 3) cause fetal hypothyroidism or hyperthyroidism, or even teratogenic, if anti-thyroid drugs are taken.
A comparison of the occurrence of pregnancy complications between pregnant women with hyperthyroidism and those with non-hyperthyroidism is as follows.
Incidence (%)
Normal control
Clinical hypothyroidism
Hyperemesis gravidarum
3.8
11.6
Spontaneous abortion
3.3
8.0
Premature birth
3.4
9.3
Perinatal death
0.9
8.1
Low weight infants
6.8
22
II: Effect of hypothyroidism on the fetus
Clinical hypothyroidism extrapolates to a greater risk of the above complications than subclinical hypothyroidism, and there are conflicting conclusions as to whether the risk of pregnancy complications is elevated in subclinical hypothyroidism.
The effect of maternal hypothyroidism on the intelligence of the offspring is shown in the following table.
Cases
Control
P-value
Number of cases
62
124
TSH(mU/l)
13.2±0.3*
1.4±0.2
<0.001< span="">
TT4(ug/dl)
7.4±0.1*
10.6±0.1
<0.001< span="">
FT4(ng/dl)
0.71±0.1*
0.97±0.07
<0.001< span="">
TPOAb (%)
77*
14
<0.001< span="">
Cases
control
P-value
1 year Intellectual development
Motor ability
95
91
105
99
0.004
0.02
2 years
Intellectual development
Motor ability
98
92
106
102
0.02
0.005
Maternal hypo-T4emia (low serum FT4, normal TSH (0.15-2.0 mIU/L)) at 12 weeks of gestation results in offspring with lower mental development and motor scores than normal controls at 1 and 2 years of age.
Therefore, patients with hyperthyroidism need to control their thyroid function within the normal range before IVF, and they can take oral propylthiouracil, which has a relatively low impact on the fetus, during pregnancy. After pregnancy, you need to consult an endocrinologist at the endocrinology department.