Getting pregnant is a lot harder than you think. It may be music to your ears if you’re young, single, and nowhere near ready for kids. But for many couples trying to conceive, the reality of infertility is daunting, stressful, and extremely life-interrupting.

1. Polycystic ovary syndrome (PCOS)

PCOS is the most common cause of infertility in women and is a condition caused by a hormonal imbalance that results in a series of small cysts on the ovaries. It also throws a woman’s periods out of the cycle, causing irregular periods, or even no period at all for a few months. Shockingly, millions of women are living with it without even knowing! With almost 50% of women of childbearing age being affected but not diagnosed, it’s best to see your doctor if you’re experiencing these subtle signs of PCOS.

2. Other hormonal factors that impact ovulation

Irregular ovulation is the main cause in about 25 per cent of infertility cases, according to Medical Director Dr Asha of GarbhaGudi, a leading Infertility clinic in Bangalore. While PCOS is the most common of these, causing 70 per cent of irregular ovulation-related infertility cases, other hormonal imbalances can impact or interrupt ovulation and lessen the chance of conceiving – ex. Throid, Estradiol, Progesterone etc.. It’s less common than PCOS and can also be caused by genetics.

3. Endometriosis

Endometriosis is a condition where the tissue that lines the uterus starts to grow in other places, like the ovaries, behind the uterus, or in the fallopian tubes, causing irritation and the development of scar tissue. Besides being extremely painful (though some women may experience no pain), it can make it very difficult to get pregnant by blocking the fallopian tubes, disrupting implantation, causing inflammation in the pelvis, and even altering egg quality. Adhesions can also form after pelvic surgeries or trauma to the reproductive organs, such as dilation and curettage (D&C) during pregnancy termination or miscarriage, or a previous C-section. While treatment can vary from person to person, surgically removing the scar tissue can improve chances of becoming pregnant especially when paired with fertility treatments such as IVF.

4. Sexually transmitted infections, other infections and growth in the reproductive system

Physical changes in the uterus, ovaries and fallopian tubes can impact the ability to get pregnant. The most likely of these is a blockage in the fallopian tubes. Tubal infection is most likely caused by an organism that starts in the cervix and then goes up into fallopian tubes, the most common: gonorrhoea and chlamydia. If left untreated, an infection can cause scarring of the fallopian tubes where the egg and sperm meet. Sometimes this blockage can be corrected surgically, but often, when the damage is extensive, fertility doctors will go straight to IVF since it just takes the tubes out of the whole process. Other things that can decrease the chances of conceiving are uterine fibroids, polyps, and cysts.

5. Waiting to get pregnant

For many women, simply waiting to get pregnant is a huge contributor to infertility. These days a big per cent of women wait to have their first child until they are 30-35. According to specialists, age is a growing cause of fertility problems and about one-third of couples trying to conceive when the woman is over 35 have difficulties.

“The most important driver [of infertility] is egg quality,” Dr Asha says. “A woman is born with all the eggs she’s ever going to have in her lifetime. In general, in her 20s, 90 per cent of her eggs are normal, and in general, in her 40s, 90 per cent are abnormal,” she adds. Of course, there are exceptions, but the longer you wait to get pregnant, the greater your chance of having abnormal or too few eggs to conceive.

Luckily, we live in a time where women can take better control of when they want to have kids. “I’m seeing more women freezing their eggs; there’s more awareness in reproductive ageing than ever before,” says Dr Asha.

6. Unhealthy body weight

Having a BMI that’s too high or low has a proven impact on the ability to get pregnant. People who are overweight or obese, have a two- to four-fold higher risk of being unable to conceive, depending on the type of obesity, and almost a six-fold risk of having miscarriages. Luckily, it’s a cause of infertility that can typically be reversed. If there’s no other contributing factor impeding fertility, over 70 per cent of women who are infertile for this reason will be able to conceive without intervention once they’re at healthy body weight.

7. Other unknown causes

In about 5 to 10 per cent of cases of couples having a tough time conceiving, all the fertility tests come back normal. This, or in cases where only minor abnormalities that wouldn’t result in infertility are found, is referred to as unexplained infertility. The course of treatment varies depending on the woman’s age—if she’s younger than 35, doctors will try simpler treatments like fertility drugs and artificial insemination; if she’s older and it seems appropriate, they may go straight to IVF.