Human placental lactogen is a hormone released by the placenta when you’re pregnant. It helps prepare your body for breastfeeding. It also regulates metabolism and insulin sensitivity to make sure the fetus gets enough nutrients. A blood test can measure the hormone to help determine the health of the placenta, fetus and pregnant person.
Human placental lactogen is a hormone released by the placenta when a person is pregnant.
The placenta is a temporary organ that develops in your uterus during pregnancy. It attaches to the wall of your uterus and provides the fetus with oxygen and nutrients. It also removes waste from fetal blood.
Healthcare providers may measure human placental lactogen with a blood test. The results can help determine whether the placenta works well and the fetus is healthy.
Human placental lactogen is also called human chorionic somatomammotropin (HCS).
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Scientists don’t fully understand all of the roles of human placental lactogen. They believe it stimulates the milk glands to prepare your body for breastfeeding.
They also believe it regulates metabolism, so your blood has more nutrients for the fetus. Human placental lactogen also may help your body be less sensitive to insulin. Insulin is a hormone that moves glucose (sugar) from your bloodstream into your cells. Decreased insulin sensitivity helps more glucose stay in your bloodstream for use by the developing fetus.
Throughout fetal development, human placental lactogen levels increase:
A blood test can detect human placental lactogen around the sixth week of pregnancy. Levels are usually higher in people expecting twins or triplets.
A healthcare provider may want to test this hormone if:
A simple blood test measures human placental lactogen. A healthcare provider inserts a needle into a vein in your arm and collects a small tube of blood for testing.
If you have an unexpected level of human placental lactogen, your healthcare provider will explain the results. They’ll take into account many other factors and may order additional tests. A high level could be an indication of diabetes or multiple fetuses.
A low level of human placental lactogen might mean:
You can’t control your hormone levels during pregnancy. But certain strategies before and during pregnancy can help you prevent gestational diabetes and high blood pressure.
If your healthcare provider orders a human placental lactogen blood test, consider asking the following questions:
A note from Cleveland Clinic
Human placental lactogen is a hormone released by the placenta when a person is pregnant. A simple blood test can measure the hormone. Results can help determine the health of the placenta, fetus and pregnant person. If your healthcare provider orders a hormone test, ask why and what the results mean for you.
Last reviewed by a Cleveland Clinic medical professional on 03/07/2023.
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