Miscarriage and loss

Miscarriage: causes, symptoms, and types

By Saurabh K Jain
With information from Peter Sam

Pregnancy miscarriage or spontaneous abortion is the loss of a pregnancy, on its own, which occurs in nearly 20% of all confirmed pregnancies. This usually occurs before 20–24 weeks of pregnancy but it is most common during the first 12 weeks. When a miscarriage occurs, the fetus, placenta, and amniotic sac are expelled by the body.

Causative factors of miscarriage

The most common cause of miscarriage is chromosomal abnormalities of the developing child. It could be due to genetic defects of the fetus caused by faulty egg and/or sperm: problems in the genes are responsible for an abnormal fetus and are found in more than half of miscarried fetuses. The risk of defective genes increases with the woman's age, especially over if she is older than 35.

Researchers have long known that during times of stress, the brain releases several hormones—including one called corticotropin-releasing hormone (CRH). In past research, women who deliver prematurely or have low-birth weight babies were often found to have high levels of CRH in their bloodstream, and other studies show a greater risk of miscarriage in women reporting stress. CRH is a hormone the brain secretes in reaction to physical or emotional stress, and it is also produced in the placenta and the uterus of a pregnant woman to trigger uterine contractions during delivery.

Fetal chromosomal abnormalities are the most common cause of sporadic miscarriage, affecting more than half of all early miscarriages. This may be due to abnormalities in the egg, sperm, or both. The usual chromosomal pattern is 46 chromosomes, arranged in 23 pairs. One of these pairs is contains the sex chromosomes: females will have two X chromosomes and males will have one X chromosome and a Y chromosome. The genes we all have are lined up along the chromosomes.

Trisomy is a type of chromosomal abnormality where there will be three chromosomes of one type rather than normal pair. This results in an embryo with 47 chromosomes instead of 46. This embryo will either abort or develop into a baby with congenital abnormalities. It is more common as reproductive age increases and the abnormalities are not very likely to recur.

In monosomy, one chromosome is missing. This condition is called Turner's syndrome when pregnancies will carry on with only one X chromosome.

The expectant mother's lifestyle during her pre-pregnancy days as well as during pregnancy may also play a major role. Smoking, drug/alcohol abuse, and exposure to hazardous materials can increase the risk of miscarriage in women. Hormonal imbalances, health issues such as infections, diabetes, immune disorders, problems of the uterus or ovaries, and so on can also cause miscarriages.

Women who have health problems such as diseases of heart, kidney, or liver; thyroid problems; and so one are at risk of a miscarriage. It has been rightly said that if an expectant mother is given adequate pre-natal care, she can greatly reduce her chances of a miscarriage.

Symptoms of a miscarriage

Vaginal bleeding is by far the most common symptom. If you have no idea you are pregnant and have vaginal bleeding that lasts for more than 2 weeks, consult your physician as it may indicate a miscarriage or other problem that needs immediate attention. If you know you are pregnant and are bleeding, it is time to call your doctor—particularly if you use up more than one sanitary pad in an hour.

Bleeding may be accompanied bylow back pain and contractions, and in some cases, clots. Women may also experience cessation of pregnancy symptoms such as tenderness in the breasts, and morning sickness.

Premature rupture of membranes and early labor

Many miscarriages begin with cramping and labor-like symptoms, but true premature rupture of membranes and early labor are usually associated with babies that are in the second or third trimester. Early labor can often be treated with drugs that relax the uterus, and women are placed on bedrest either at home or in the hospital.

Sometimes, however, the baby comes anyway. This, known as stillbirth if it occurs after 20 weeks, is one of the most traumatic of losses: you will hold and see your baby and beg him or her to breathe. For some women, the baby will even be born alive, but only live for a few minutes, hours, or days. There really is nothing harder in life than this.

Types of miscarriages

There are several types of pregnancy miscarriages. An expectant mother who suffers light uterine bleeding and is found to have a closed cervix, the condition is called as a threatened miscarriage. When the expectant mother has uterine bleeding and an open cervix, the condition is referred to as an inevitable miscarriage. When the expectant mother has lost the fetus and the products of conception, it is referred to as a complete miscarriage. When the embryo dies inside the womb and the products of conception are not expelled, it is referred to as a missed miscarriage. Miscarriage that occurs past 20 weeks' gestation is known as stillbirth. Recurrent miscarriage occurs in some women due to any of the causes listed above.

In the vast majority of cases, there is no way of preventing a miscarriage; however, having a miscarriage does not mean that you won't be able to get pregnant again, and most women go on to have a successful pregnancy. If women consult a physician before they consider getting pregnant and plan a pregnancy, exercise caution, and take the necessary precautions, they ought to have a successful healthy pregnancy.