Birth spacing, pregnancy spacing, inter-birth interval (IBI) or inter-pregnancy interval refers to how soon after a prior pregnancy a woman becomes pregnant or gives birth again. There are health risks associated both with pregnancies placed closely together and those placed far apart, but the majority of health risks are associated with births that occur too close together. The WHO recommends 24 months between pregnancies. A shorter interval may be appropriate if the pregnancy ended in

abortion Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pregn ...

miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical ...

, typically 6 months. If the mother has had a prior C-section, it is advisable to wait before giving birth again due to the risk of uterine rupture in the mother during childbirth, with recommendations of a minimum inter-delivery interval ranging from a year to three years. Pregnancy intervals longer than five years are associated with an increased risk of

pre-eclampsia Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease ...

. The global public health burden of short inter-pregnancy intervals is substantial. Family planning can help increase inter-pregnancy interval.

Factors influencing birth spacing

Family planning, such as the use of contraceptives can increase inter-pregnancy interval.

Breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that bre ...

and extended breastfeeding can also increase birth spacing due to lactational amenorrhea. Cultural and religious attitudes towards both sex and the use of contraceptives, price and availability of health care, and poverty are all factors which can affect inter-pregnancy intervals.

Health risks

Short inter-pregnancy interval

Short inter-pregnancy interval is associated with an increase in maternal mortality, stillbirth, and

child mortality Child mortality is the mortality of children under the age of five. The child mortality rate, also under-five mortality rate, refers to the probability of dying between birth and exactly five years of age expressed per 1,000 live births. It en ...

. Inter-pregnancy interval of lower than 18 months is associated with an increased risk of pre-term birth. Short inter-pregnancy interval after a prior C-section can be a

contraindication In medicine, a contraindication is a condition (a situation or factor) that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a reas ...

for having a vaginal birth after a prior C-section (

VBAC In case of a previous caesarean section a subsequent pregnancy can be planned beforehand to be delivered by either of the following two main methods: * Vaginal birth after caesarean section (VBAC) * Elective repeat caesarean section (ERCS) Both h ...

). In one study inter-pregnancy intervals shorter than 6 months were associated with 2-3 times increased risk of uterine rupture, major morbidity, and

blood transfusion Blood transfusion is the process of transferring blood products into a person's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but m ...

during vaginal delivery in mothers with at least one prior C-section. Complications of a short inter-pregnancy interval are lower after an abortion or miscarriage compared to a full-term pregnancy.

Long inter-pregnancy interval

An inter-pregnancy interval of greater than five years is associated with an increased risk of

Public health

The global

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...

burden of short inter-pregnancy intervals is substantial. In developing countries, children born two years or earlier after an older sibling were at a 60% increased risk of death in infancy, while those born between two and three years had a 10% increase, compared with those born after intervals of four to five years. Various organisations, including the

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...

have identified birth spacing as an important area of public health intervention.

Epidemiology

In one study, the average birth interval across all countries was 32.1 months (2.7 years). The region with the greatest percentage of short interbirth intervals was central Asia, where a third of children were born less than 24 months apart. The region with lowest burden was Sub-Saharan Africa, with 20% of births having an interval of less than 24 months. Birth intervals have been found to be higher in traditional hunter-gatherer societies. The median birth interval of the Gainj people of the

New Guinea Highlands The New Guinea Highlands, also known as the Central Range or Central Cordillera, is a long chain of mountain ranges on the island of New Guinea, including the island's tallest peak, Puncak Jaya , the highest mountain in Oceania. The range is home ...

has been reported as 3.6 years (43 months), and that of the !Kung people of Africa as 3.7 years (44 months).

In animals

The inter-birth intervals in wild apes are reported to be significantly longer than those in

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s, with median birth intervals at 3.8 years for

gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four ...

s, 5.6 years for chimpanzees and 7.7 years for

orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the gen ...

References

{{Human reproductive health, state=collapsed Childbirth Human pregnancy Public health