Nulliparous is the clinical term for a lady who has never conceived an offspring either by decision or for some other explanation. This term additionally applies to ladies who have brought forth a stillborn infant, or an infant who was in any case not ready to make due outside the belly A nulliparous woman has never given birth. It includes women who have experienced spontaneous miscarriages and induced abortions before the mid-point of pregnancy, but not women who have experienced pregnancy loss after 20 weeks. Prolonged nulliparity is a risk factor for breast cancer. For instance, a meta-analysis of 8 population-based studies in the Nordic countries found that never giving birth was associated with a 30% increase in the risk of breast cancer compared with women who have given birth, and for every 2 births, the risk was reduced by about 16%. Women having their first birth after the age of 35 years had a 40% increased risk compared to those with a first birth before the age of 20 years.

Nulliparous is the medical term for a woman who has never given birth either by choice or for any other reason. This term also applies to women who have given birth to a stillborn baby, or a baby who was otherwise not able to survive outside the womb
Nulliparity has been shown to be a risk factor for preeclampsia (PE) with a reported incidence of up to 2–3 times higher than multiparous pregnancies

Reproductive events such as menarche, pregnancy, and menopause influence a woman's risk for a number of diseases. For example, the incidence of breast cancer is higher in women who have longer estrogen exposure due to early menarche, late menopause, or nulliparity. Conversely, a naturally high exposure to estrogen over a lifetime may decrease the chance of developing osteoporosis. Some studies also indicate that estrogen influences the risk for age-related diseases of the central nervous system. A large body of basic science research has provided possible mechanisms by which estrogen might influence brain aging. These include modulation of acetylcholine4 and other brain neurotransmitters, enhanced dendritic sprouting, interaction with trophic factors, prevention of cerebral ischemia, protection against oxidative stress, and modulation of lipoprotein isoforms. Clinical studies of estrogen replacement therapies have shown mixed results, with the two published prospective studies demonstrating a reduced risk of Alzheimer's disease (AD) with hormone therapy and retrospective studies yielding mixed results. Current data do not support the use of hormone replacement therapy (HRT) in the treatment of AD. Studies of HRT on age-related decline in particular cognitive domains have also produced mixed results, with positive studies showing an appreciably consistent effect on verbal memory.