What Causes Secondary Infertility?
Many women have no difficulty getting pregnant initially, but when trying to grow a family again, challenges can arise. Secondary infertility describes difficulty achieving pregnancy after 1 or more prior births. Many couples expect a similar experience with future conception attempts, but new challenges can arise due to age, health changes, or the development or worsening of reproductive conditions. Awareness of secondary infertility allows couples to plan accordingly.
Common underlying causes
Infertility is incredibly common, affecting approximately 1 in 6 couples. An initial diagnosis of infertility is often attributed to fallopian tube damage, ovulation disorders such as polyendocrine metabolic ovarian syndrome (PMOS), and uterine fibroids or polyps. In some cases, couples are given a diagnosis of unexplained infertility when no obvious cause can be found. Low sperm count, poor motility, and abnormal sperm shape in the male partner may also play a role. In some cases, these issues may be mild in a first pregnancy but worsen over time. Increasing maternal age, new health conditions, and reproductive changes after a first pregnancy are primary causes of secondary infertility. A new partner or certain lifestyle changes such as excessive weight gain can also impact subsequent pregnancy chances
How does age affect fertility?
Advancing maternal age leads to a gradual decline in ovarian reserve, meaning fewer eggs remain available for fertilization. Egg quality also decreases over time, increasing the likelihood of chromosomal abnormalities. Hormonal signaling may become less predictable, affecting the timing of ovulation. While pregnancy at 25 or 30 may have been relatively straightforward, older women often experience a longer time to conception and higher rates of miscarriage. Early evaluation can help identify reduced egg count and guide appropriate next steps. In some cases, egg freezing may be recommended to increase the odds of a second pregnancy.
New health conditions
Chronic health conditions that develop later in life can interfere with fertility. Autoimmune disorders may disrupt normal reproductive function through inflammation or hormonal imbalance. Thyroid disease can affect ovulation and menstrual cycle regularity. Lupus can cause diminished ovarian reserve (DOR), irregular ovulation, and recurrent miscarriage. Metabolic conditions, including insulin resistance, may further impair ovarian function. Careful management of underlying health issues can improve the likelihood of successful conception.
Reproductive changes over time
In some cases, reproductive conditions may evolve or worsen after a prior pregnancy. Disorders such as PMOS may become more pronounced, leading to irregular ovulation. The number of fibroids can increase significantly in the time between a first and second attempt at pregnancy, making implantation more difficult to achieve. Prior pregnancy complications, including infection or cesarean delivery, can result in scar tissue that affects the uterus or fallopian tubes.
When to seek evaluation
For women under 35, a fertility evaluation is typically recommended after 12 months of unsuccessful attempts at pregnancy. Women aged 35 or older should consider evaluation after 6 months. Women over 40 or individuals with known fertility concerns should be seen as soon as possible. Initial assessment often includes hormone testing, imaging, and a semen analysis (SA) for the male partner. Seeking care early can help identify known causes of secondary infertility and allow for the development of an individualized treatment plan.
Secondary success is possible
Despite a diagnosis of secondary infertility, many women go on to successfully get pregnant again. Intrauterine insemination (IUI) and in vitro fertilization (IVF) are excellent treatments that can overcome many barriers to conception. With early action, appropriate medical support, and individualized care, many families ultimately achieve pregnancy.
