Posts Tagged ‘embryo’

What is a molar pregnancy?

Thursday, August 1st, 2013

In a molar pregnancy, the early placenta develops into an abnormal mass (called a hydatidiform mole) that looks a little like a bunch of white grapes. The embryo either does not form at all or is malformed and cannot survive. About 1 in 1,500 pregnancies is molar.

There are two types of molar pregnancy: complete mole (there is no embryo and no normal placental tissue); and partial mole (there is an abnormal embryo, and there may be some normal placental tissue.) Both types of molar pregnancy are caused by an abnormal fertilized egg.

In a complete mole, all of the fertilized egg’s chromosomes (tiny thread-like structures in cells that carry genes) come from the father. Normally, half come from the father and half from the mother. In a complete mole, shortly after fertilization, the chromosomes from the mother’s egg are lost or inactivated, and those from the father are duplicated.

In most cases of partial mole, the mother’s 23 chromosomes remain. However, there are two sets of chromosomes from the father (so the embryo has 69 chromosomes instead of the normal 46). This can happen when two sperm fertilize an egg.

Molar pregnancy poses a threat to the pregnant woman because it can occasionally result in rare pregnancy-related types of cancers called invasive mole and choriocarcinoma.

The most common symptom of a molar pregnancy is abnormal vaginal bleeding in the first three months of pregnancy. Other symptoms may include severe nausea and vomiting, rapid uterine growth, high blood pressure, cysts (fluid-filled sacs) on the ovaries, and hyperthyroidism.

Health care providers use an ultrasound to diagnose a molar pregnancy. The provider also measures the levels of the hormone hCG in the mother’s blood, which often are higher than normal with a molar pregnancy.

A molar pregnancy is a frightening experience. Not only does the woman lose a pregnancy, she learns that she has a slight risk of developing cancer. To protect her, all molar tissue must be removed from the uterus. This usually is done with a D&C. Occasionally, when the mole is extensive and the woman has decided against future pregnancies, she may have a hysterectomy.

After mole removal, her provider again measures the level of hCG. If it has dropped to zero, the woman generally needs no additional treatment. However, the provider will continue to monitor hCG levels for 6 months to 1 year to be sure there is no remaining molar tissue. It’s important that a woman not become pregnant during this time, because a pregnancy would make it difficult to monitor hCG levels.

After the uterus is emptied, about 20 percent of complete moles and less than 5 percent of partial moles continue on. The remaining abnormal tissue may continue to grow in the wall of the uterus. This is called persistent gestational trophoblastic disease (GTD) or invasive mole. The diagnosis is made when hCG blood levels stop decreasing or begin to increase. Treatment with one or more cancer drugs cures persistent GTD nearly 100 percent of the time. Rarely, a cancerous form of GTD, called choriocarcinoma, develops and spreads to other organs. Use of multiple cancer drugs is usually very successful at treating this cancer.

All of this may sound scary, but the good news is that a woman who has had molar pregnancy usually can go on to have healthy pregnancies. The risk that a mole will develop in a future pregnancy is only about 1 to 2 percent.

Understanding ovulation and fertilization

Monday, July 8th, 2013

coupleWhile it’s obvious to many, there are plenty of folks who don’t really understand the basic mechanisms about how we get pregnant. If you have been trying for a while without success, it can be frustrating. Maybe this will help.

A woman’s ovaries release an egg every month, about 14 days before the first day of her period. This is called ovulation. When a couple has sexual intercourse (and does not use birth control) around the time of ovulation, a man’s sperm swim to meet the woman’s egg. When a sperm penetrates the egg, it’s called fertilization or conception. The fertilized egg (embryo) then travels to the woman’s uterus (womb), where it burrows into the lining of the uterus and begins to grow.

The best time to get pregnant is a few days before ovulation or the day of ovulation. This is because a man’s sperm can live up to 72 hours after intercourse and a woman’s egg is fertile for 12 to 24 hours after its release. Knowing when you’re ovulating can boost your chances of getting pregnant. If your periods are regular, use an ovulation calculator to get an idea of when you’re most fertile. If your periods are irregular, use one of the following methods. Talk to your health care provider to learn more about the most effective way to use these.
• Purchase a basal body thermometer. Use it to take your temperature before you get out of bed every day. Your temperature goes up by 1 degree when you ovulate.
• Check the mucus in your vagina. It may become thinner, more slippery, clearer and more plentiful just before ovulation.
• Purchase an ovulation prediction kit. Use it to test your urine for a substance called luteinizing hormone (LH). LH increases each month during ovulation.

Having sex as close as possible to ovulation can improve your chance of getting pregnant. Select and watch our video on ovulation and pregnancy to learn more.

Fertility and multiples

Wednesday, August 22nd, 2012

In this video, Dr. Siobhan Dolan talks with a woman about fertility treatment and how to lower one’s chances of getting pregnant with twins, triplets or more.

How your baby grows – month 2

Monday, September 5th, 2011

pregnant-couple

Your baby:

By the end of the second month, your baby is about an inch long and still weighs less that 1/3 ounce. Your baby’s major body organs, like the brain, heart and lungs, are forming. The placenta is working. The placenta grows in your uterus and supplies the baby with food and oxygen through the umbilical cord. Your baby’s ears, ankles, wrists, fingers and toes are formed. Eyelids form and grow but are sealed shut.

Your body:

Your breasts may till be sore and are getting bigger. Your nipples and the area around them begin to get dark. You have to go to the bathroom more often because your uterus is growing and pressing on your bladder. You may still have morning sickness. You may feel tired and need to rest more often. Your body is busy making more blood.

How your baby grows – month 1

Monday, August 29th, 2011

pregnant-coupleEvery Monday for the next nine weeks, I’ll be writing about the fascinating changes that occur within a developing baby and the changes a woman experiences during her pregnancy. Here’s what goes on in your first month.

Your baby:

By the end of the first month, your baby is about ¼ inch long. Tiny limb buds appear that will grow into your baby’s arms and legs. Your baby’s heart and lungs begin to form. By the 22nd day, the heart starts to beat. Your baby’s neural tube begins to form and will become the brain and spinal cord.

Your body:

Your body is making lots of hormones that help your baby grow. But hormones can make you feel moody and cranky. Your breasts may get bigger and may hurt and tingle. You may feel sick to your stomach. This is called morning sickness, even though it can happen at any time of day or night. (Try eating some crackers and smaller meals.) You may crave some foods or hate foods you usually like. You may feel very tired. It’s important to rest whenever you can.

The placenta and fetal circulation

Thursday, January 14th, 2010

insideThe placenta is a remarkable organ that connects the mother’s blood supply with that of the developing fetus through the umbilical cord.  It transports oxygen and nutrients to the baby’s blood and returns the baby’s waste to the mom’s blood for disposal through her kidneys.

The placenta, formed from the same cells as the embryo, attaches to the wall of the uterus and to the umbilical cord. Oxygen-rich, nutritious blood travels from Mom to the fetus by the umbilical vein in the umbilical cord.  The umbilical vein delivers the blood to the liver and then much of it travels on to the right side of the heart. Here it mixes with blood of the fetus and is sent on through two special openings, bypassing the nonfunctioning lungs, into the left side of the heart for distribution to the entire body.  After completing the circuit, the blood that has delivered oxygen and nutrients to the fetus now flows via major vessels back to the umbilical cord where the two umbilical cord arteries carry it back to the placenta.

While the placenta allows oxygen and nutrients to pass through it, it also filters out many potentially harmful substances and infections. Near term, the placenta produces hormones that play a role in triggering labor and delivery.  After the baby is born, the placenta’s job is done and the placenta is delivered as the afterbirth.

In some cases the placenta may not develop correctly or function as well as it should. It may be too thin, too thick or have an extra lobe, or the membranes may be improperly attached.  Most of these issues are detected via ultrasound.  Signs of a problem include vaginal bleeding and/or continuous abdominal pain.  If you’re pregnant and have questions about your placenta, ask your doctor about it during an ultrasound.