Introduction
Pregnancy is a special time when a woman’s body changes a lot. The hormones inside go up and down. Two health problems can happen during pregnancy that doctors need to watch very carefully. One is thyroid trouble. The other is diabetes that shows up for the first time when a woman is pregnant. Both of these can hurt the baby if they are not found and treated early.1
Doctors now know that thyroid problems are quite common in pregnant women. Many women have what we call subclinical hypothyroidism. This means the thyroid is not working right, but the woman does not feel sick. Diabetes that starts in pregnancy is also very common. We see it in about one in seven pregnant women. Both problems need quick treatment to keep the baby safe.2
Part One: Thyroid Problems in Pregnancy
Finding Thyroid Problems
Thyroid tests have gotten much better over the years. The best test now is called the fourth generation TSH test. It can find even very small amounts of thyroid trouble. The test looks for something called TSH, which is a hormone that tells the thyroid what to do.3
Doctors need to know the right numbers. If TSH is very low, the thyroid is too active. We call this hyperthyroidism. We cannot say a woman has this problem unless the TSH is below 0.01. If TSH is high, the thyroid is lazy. This is hypothyroidism. The normal number is not the same for pregnant women as for other people.4
The Right TSH Numbers for Pregnant Women
The American Thyroid Association gives different numbers depending on which three months of pregnancy a woman is in. In the first three months, TSH should be between 0.1 and 2.5. In the second three months, it can be a bit higher, between 0.2 and 3.0. In the last three months, it should be between 0.3 and 3.0.5
These numbers are very important. They are different from the regular numbers for women who are not pregnant. Doctors must use the right numbers or they might miss thyroid trouble.6
Subclinical Hypothyroidism
Many pregnant women have what we call subclinical hypothyroidism, or SCH. This happens when the TSH is between 2.5 and 3.0. The woman feels fine. There are no clear signs. But the baby can still be hurt. This type of thyroid problem is one of the top reasons why women cannot get pregnant. It also causes miscarriages.7
Even when the TSH is between 3.0 and 5.0, doctors should treat it with a medicine called levothyroxine. If the woman also has something called anti-TPO antibody, she definitely needs treatment. These antibodies attack the thyroid and can hurt the baby.8
Thyroid Antibodies and Miscarriage
Some women have antibodies, which are like soldiers in the blood that attack the thyroid. We call this thyroperoxidase antibody, or TPO. This is bad. It makes the woman more likely to lose the baby early on. It also makes early birth more likely.
If a woman has lost three babies in a row before ten weeks, and she has TPO antibodies, she needs special treatment. Doctors give her shots of a medicine called immunoglobulin. They also give her a blood thinner called heparin and a low dose of aspirin. This helps keep the baby safe. The woman takes this medicine for several months of pregnancy. She stops the aspirin at week 34 and the heparin at week 37, or earlier if she loses the baby.9
Thyroid Screening and Monitoring
Every pregnant woman should get a thyroid test before she gets pregnant or very early on. Women who already have thyroid trouble need tests more often. After the woman starts medicine, the doctor checks the TSH again after four to six weeks. Then the doctor keeps checking to make sure the medicine is working right. The goal is to keep the TSH below 3.0 to stop miscarriages.10
Part Two: Diabetes in Pregnancy
What Is Gestational Diabetes?
Gestational diabetes mellitus, or GDM, is diabetes that starts for the first time during pregnancy. It happens because the baby and the placenta make hormones that fight the insulin in the mother’s blood. The mother’s body tries to make more insulin, but sometimes it cannot keep up. Then the blood sugar gets too high.
This problem is very common. It happens in about one in seven pregnant women. If it is not treated, high blood sugar can hurt the baby. Babies of mothers with untreated GDM are bigger than normal. They can get stuck during birth. After the baby is born, the baby’s blood sugar can drop too low. The baby might get low oxygen. Birth injuries happen more often.11
Finding Gestational Diabetes
Doctors test all pregnant women between 24 and 28 weeks. The test is simple. The woman drinks a sweet drink with 75 grams of sugar. The doctor checks her blood sugar after two hours. If the number is 140 or higher (or 7.8 in the other number system), the woman probably has GDM.
This test is the same test used all over the world. It is the best way we know to find GDM. Finding it early is very important because treatment works well.12
Goals for Blood Sugar
The goal of treatment is to keep blood sugar in a safe range. When the woman wakes up and has not eaten, her blood sugar should be between 4.5 and 5.0. After meals, it should be below 7.0. Some doctors also check something called HbA1c, which shows the average blood sugar over two or three months. The goal is 6 percent if this can happen without the woman’s blood sugar dropping too low.
When the blood sugar is very low, below 70, the woman feels shaky and scared. This is called hypoglycemia. Doctors try to keep blood sugar above 70 to stop this from happening.13
Insulin in Pregnancy
Insulin is the best medicine for GDM. The body’s need for insulin changes as pregnancy goes on. Around 16 weeks, the need for insulin starts to go up. By the end of pregnancy, a woman might need two or four times as much insulin as she did before she got pregnant. Then after the baby is born, the need drops right back down.
There are many types of insulin. Some work fast, in about five to fifteen minutes. Some work in the middle, taking two to four hours. Some work slow and last a long time. The doctor picks the right type for each woman.14
Medicines That Don’t Work as Well
Some medicines that doctors use for diabetes are not as good as insulin in pregnancy. A medicine called metformin crosses into the baby’s blood and can build up there. It should not be used in women with high blood pressure or those at risk of the baby not growing right. Another medicine called glyburide does not have good safety data for babies. Insulin is much safer.15
Other Health Problems in Pregnancy with Diabetes
Pregnant women with diabetes often have high blood pressure too. If the blood pressure is 140 over 90 or higher, the doctor should start treating it. Newer studies show that starting treatment early gives better results than waiting until the blood pressure is very high. The medicines that work best and are safe are labetalol, methyldopa, nifedipine, and clonidine.16 Water pills, called diuretics, should not be used. ACE inhibitors should not be used either because they can hurt the baby’s kidneys.
Cholesterol medicines like statins must be stopped before pregnancy or as soon as the woman finds out she is pregnant.17
Insulin Just Before Delivery
During labor, the doctor controls the insulin and sugar very carefully. The woman gets an IV with sugar water. For every unit of insulin, the body uses up 2.5 to 5 grams of sugar. The doctor watches the blood sugar closely and keeps it between 6 and 8. A special IV called GKI, which mixes insulin, sugar, and potassium, works very well. It keeps the blood sugar steady during the whole labor.18
After Delivery
Right after the baby is born, the mother’s body changes fast. The placenta comes out, and suddenly the mother’s body does not fight insulin anymore. Her body becomes very sensitive to insulin again. If she was taking insulin for GDM, she usually does not need it after delivery. Over the next one or two weeks, everything goes back to normal.19
But the story is not over. Women who had GDM must get tested every one to three years for the rest of their lives. Many of them will get diabetes later. About nine in ten women who had GDM will get it again if they get pregnant again.20,21
Conclusion
Thyroid problems and diabetes in pregnancy are not small things. They are common and they can hurt both mother and baby. But they are also things that doctors can find and treat. The key is to test early and watch carefully. With the right treatment and follow-up, mothers and babies do well. Teamwork between the doctor, the woman, and her family makes all the difference. Every pregnant woman deserves these checks and this care.
Author of this article
Dr. A S M Towhidul Alam, MBBS, MCPS, MD, MRCP, Ph. D, Endocrinologist, Associate Professor (Rtd), Chattogram Medical College
Reference
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