Are you worried you’re experiencing a miscarriage? Read more about the signs and symptoms here.

As many as 10 to 15 percent of confirmed pregnancies end in a miscarriage, and this figure does not include the number of miscarriages that occur before a woman even realizes she is pregnant.

The majority of miscarriages occur in the first 12 weeks of pregnancy. The first 10 weeks of a pregnancy are considered embryonic life. “Many babies do not make the transition to a fetus,” says Dr. Doug Wilson, department head of obstetrics and gynecology at the University of Calgary. “The development process from embryo to fetus at 10 menstrual weeks (or eight embryonic weeks) is a major step, and 25 to 30 percent of pregnancies end in an early loss.” The embryo may not be developing properly, there may have been a genetic defect or abnormality passed on to the baby from the male or female, there could be an infection or there may be hormonal abnormalities. Chromosome translocation, wherein a piece of one chromosome breaks off and is joined with another chromosome, or where pieces of two chromosomes switch places, also increases the chance of a miscarriage, even if the affected chromosome wouldn’t necessarily have resulted in a physical or mental handicap in the child. “An imbalanced chromosome translocation, with loss or gain, increases the likelihood of hormonal imbalance and, therefore, miscarriage, depending on the size of the loss or gain,” says Dr. Wilson. Miscarriages can also be the result of a structural abnormality in the uterus.

Even if a fetus makes the transition from embryonic life, it may not be healthy. An unhealthy fetus will usually be miscarried in the first two weeks after the embryonic stage, which is why those first 12 weeks of pregnancy are so crucial.

The number of miscarriages may appear to be rising, but miscarriages have actually decreased in Canada since the early seventies. Even so, increasing numbers of women are having children later in life and the rates of miscarriage for women over 30 are higher.

“Biologically, the ideal age to have a baby is 22,” says Beverly Hanck, executive director of the Infertility Awareness Association of Canada, who had her first child at 37. “By age 30 you have a 15 percent chance of having a miscarriage, and by age 40 you have a 50 percent chance of miscarriage.” she says. “[However], young women today are not usually planning a family or have even met someone by 22. I would say ideally, start trying no later than age 32.”

If you’ve had a miscarriage, learn more about finding support to help move on.