Conjoined twins are the result of a single fertilized egg that doesn't fully separate into two individuals during early embryo development./SCREENGRABKenya has joined the world in observing World Conjoined Twins Day.
The day, usually marked on 24 November of every year, is designated by the United Nations General Assembly to raise awareness about the rare condition of conjoined twins and to advocate for the well-being, rights, and social inclusion of those affected.
The UN defines conjoined fetuses as a rare type of identical twins that share a placenta and an amniotic sac, when the embryo divides at 13-15 days from conception.
“The incidence ranges from 1 out of 50,000 to 1 out of 100,000 live births. Female fetuses are more commonly affected, as the ratio of female to male is 3:1,” they note.
Conjoined twins, the UN notes, present unique medical, ethical, and social challenges that require coordinated care and long-term support.
The observance emphasises a life-course approach, ensuring that interventions extend beyond the neonatal period to encompass ongoing health management, social integration, and ethical considerations.
This is done in collaboration with international agencies, local health systems, and civil society organisations.
Earlier in August 2025, Kenyatta National Hospital (KNH) provided specialised care for a set of conjoined twin girls born on August 13, 2025, at Naivasha County Hospital.
The twins, who were delivered via caesarean section and weighed a combined 3.6 kilogrammes at birth, were urgently referred to KNH’s Paediatric Intensive Care Unit (PICU) in the early hours of August 14.
The hospital confirmed that the babies are conjoined at the abdomen and pelvis, and medical assessments have revealed they do not have anal openings, necessitating emergency intervention.
“To save their lives, the specialised paediatric surgical team performed an emergency colostomy on August 17, 2025,” said the then CEO Evanson Kamuri.
The procedure involved creating an opening to bypass the intestinal obstruction and allow for the safe passage of stool.
Healthline offers insights into how conjoined twins develop.
“Conjoined twins may be connected at the chest, abdomen, head, or some other part of the body and often share organs in these areas,” Healthline states.
They develop from a single fertilised egg, making them monozygotic (from a single ovum) or identical twins.
Unlike typical identical twins who fully separate during early embryonic development, conjoined twins arise when the embryo either partially fails to split, known as the fission theory, or when two initially separate embryos fuse together, referred to as the fusion theory.
“During a typical identical twin pregnancy, the embryo divides at about 13 days after fertilisation. With a conjoined twin pregnancy, this division is delayed. Sometime between days 13 and 15, the embryo begins to divide but stays fused together in certain areas of the developing bodies,” Healthline further explains.
This results in twins that remain physically connected at various parts of their bodies, often sharing internal organs, which significantly influences their medical care and survival prospects.
Globally, conjoined twinning is exceedingly rare, with the exact type and location of connection varying widely, each presenting unique medical challenges.
Types of conjoined twins
The most common form is thoraco-omphalopagus twins, who are joined at the chest and abdomen, accounting for about 28 percent of conjoined twin pregnancies, according to Healthline.
This type often involves shared vital organs such as the heart or liver, making surgical separation particularly complex.
Thoracopagus twins, joined primarily at the chest, make up around 18.5 percent of cases and similarly may share cardiac structures.
Omphalopagus twins are connected at the abdomen and represent about 10 percent of cases; they typically share liver or gastrointestinal tissues.
Heteropagus twins, also accounting for roughly 10 percent, are parasitic twins in which one twin is underdeveloped and dependent on the other for survival.
Craniopagus twins: These twins are joined at the head. This type makes up around 6 percent of conjoined twin pregnancies.
Other rarer types include pygopagus twins, joined at the sacrum or perineum; rachipagus twins, connected at the spine; ischiopagus twins, joined at the lower abdomen or pelvis; and cephalopagus twins, who are joined from the head to the belly button.
Each type has distinct implications for survival, surgical feasibility, and long-term care, illustrating the medical complexity of this rare condition.
The type and complexity of the connection strongly influence medical decisions, surgical options, and survival outcomes.
Symptoms and diagnosis
Healthline notes that pregnancy with conjoined twins may not have specific symptoms but often presents like a multiple pregnancy, with rapid early weight gain, severe morning sickness, extreme fatigue, intense breast tenderness, and a larger-than-expected uterus.
"There are no specific symptoms you may experience if you’re pregnant with conjoined twins. Instead, you may have symptoms similar to those in a typical pregnancy with muiltiples," it states.
These intensified symptoms are linked to higher levels of hCG (hormone produced by the body during pregnancy to support fetal growth.in the body).
While elevated hCG may suggest a multiple pregnancy, it cannot reliably indicate conjoined twins.
Ultrasound can detect twins and whether they are joined as early as the first trimester, while MRI provides detailed, radiation-free imaging of their connection and shared organs for accurate diagnosis.
Can conjoined twins be separated?
According to Healthline, pregnancy with conjoined twins is high-risk, requiring care from a maternal-fetal medicine specialist.
Delivery is usually by C-section around 34–35 weeks, followed by NICU support. About 25 percent survive long enough for separation surgery, which occurs case-by-case between 3 months and 3 years, carrying risks like organ failure, post surgical infection, and bleeding.
The survival rate has, however, improved with advances in prenatal imaging, surgical techniques such as the colostomy performed by KNH, and multidisciplinary care.
Other treatment options
Healthline notes that there is no standard treatment for conjoined twins, and care is tailored to each pair’s unique connection and health needs.
"There’s no standard treatment for conjoined twins. Instead, your doctor will take into consideration the babies’ health and any other special circumstances that are unique to their physical connection," it states.
A multidisciplinary medical team guides decisions on supporting their growth, development, and overall well-being.
Treatment options may include physical therapy to strengthen muscles, occupational therapy to enhance daily function, and specialised devices to improve mobility and independence, helping twins achieve the best possible quality of life
In Kenya, cases such as the recent conjoined twins born in Naivasha, who were connected at the abdomen and pelvis and shared a single large intestine, illustrate both the medical complexity and the importance of specialized pediatric care.
World Conjoined Twins Day serves not only to recognise the rarity and medical intricacies of conjoined twinning but also to advocate for dignity, social inclusion, and support for affected families.
It underscores the importance of research, early diagnosis, specialized surgical and neonatal care, and societal awareness.
In Kenya and around the world, the observance encourages governments, health institutions, and civil society to invest in care, raise awareness, and support families so that conjoined twins are treated with compassion, equity, and inclusion.
Emergency interventions and intensive care management were
necessary to stabilise the twins, highlighting the critical need for
multidisciplinary expertise and long-term support systems in the country.
