A woman’s ability to have a child using assisted reproduction technologies (ART) such as test-tube fertilization plummets to a 4 percent success rate after she turns 42, according to a U.S. government study published on Friday.

As with natural conception, the younger a woman is when trying, the greater the likelihood of success with each attempt, the Centers for Disease Control and Prevention found.

“Women in their 20s and early 30s who used ART had the most success with pregnancies and single live births,” said Victoria Wright, a public health analyst who helped write the report. ART referred to assisted reproductive technology.

“However, success rates declined steadily once a woman reached her mid-30s. This is a reminder that age remains a primary factor with respect to pregnancy success, and younger women have greater success than older women, even with technology,” Wright added in a statement.

According to the report, more than 45,000 babies were born in the United States with the help of assisted reproductive technology in 2002, up from 40,687 babies in 2001.

There were 115,392 attempts at conceiving a child using assisted reproductive technology in 2002 compared to 107,587 tries in 2001.

Most attempts were by in-vitro fertilization, or IVF, also known as test-tube baby technology, in which a woman’s egg and her partner’s sperm are allowed to make contact in a lab dish, and resulting embryos are implanted in the woman’s uterus or sometimes frozen for later use.

The report found that 28.3 percent of ART procedures resulted in the birth of one or more babies for women who used their own freshly fertilized eggs. About 35 percent of all births using ART led to multiple births - twins, triplets or more - compared to a 3 percent rate among the general population.

An analysis found that 37 percent of assisted attempts in women under 35, using a woman’s own egg and her partner’s sperm, led to a live birth.

This success rate fell to 21 percent among women aged 38 to 40, to 11 percent among women aged 41 and 42 and to 4 percent among women older than 42.

The report is based on information given to the CDC by 391 fertility clinics throughout the United States.