Women's health refers to the health of women, which differs from that of men in many unique ways. Women's health is an example of population health, where health is defined by the World Health Organization as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity". Often treated as simply women's reproductive health, many groups argue for a broader definition pertaining to the overall health of women, better expressed as "The health of women". These differences are further exacerbated in developing countries where women, whose health includes both their risks and experiences, are further disadvantaged. Although women in industrialised countries have narrowed the gender gap in life expectancy and now live longer than men, in many areas of health they experience earlier and more severe disease with poorer outcomes. Gender remains an important social determinant of health, since women's health is influenced not just by their biology but also by conditions such as poverty, employment, and family responsibilities. Women have long been disadvantaged in many respects such as social and economic power which restricts their access to the necessities of life including health care, and the greater the level of disadvantage, such as in developing countries, the greater adverse impact on health. Women's reproductive and sexual health has a distinct difference compared to men's health. Even in developed countries pregnancy and childbirth are associated with substantial risks to women with maternal mortality accounting for more than a quarter of a million deaths per year, with large gaps between the developing and developed countries. Comorbidity from other non reproductive disease such as cardiovascular disease contribute to both the mortality and morbidity of pregnancy, including preeclampsia. Sexually transmitted infections have serious consequences for women and infants, with mother-to-child transmission leading to outcomes such as stillbirths and neonatal deaths, and pelvic inflammatory disease leading to infertility. In addition infertility from many other causes, birth control, unplanned pregnancy, unconsensual sexual activity and the struggle for access to abortion create other burdens for women.