Twins in Grand Rapids, Michigan: Identical and Fraternal

Multiple births are becoming more common across the United States, including here in Grand Rapids, Michigan. This is largely due to people choosing to have children later in life and the increased use of fertility treatments. If you’re expecting twins in Grand Rapids, understanding the difference between identical and fraternal twins—and the unique health considerations—can help you prepare and find the right local care.

Identical vs. Fraternal Twins

How Identical Twins Form

Identical twins (also called monozygotic twins) develop when one fertilized egg (ovum) splits into two. Each half then grows into a baby with the same genetic information. These twins:

  • Are always the same sex
  • Often look very similar
  • Share the same blood type and many physical traits

About one in three sets of twins are identical. The exact reason a fertilized egg splits is still unknown.

Around one quarter of identical twins are “mirror image” twins. In these pairs, features on the right side of one twin match the left side of the other twin (for example, hair whorls or birthmarks on opposite sides).

How Fraternal Twins Form

Fraternal twins (also called dizygotic twins) occur when two separate eggs (ova) are fertilized by two separate sperm. These twins:

  • Are genetically similar to regular siblings
  • Can be the same sex or different sexes
  • May look very similar—or quite different

About two in three sets of twins are fraternal. Fraternal twins are more common than identical twins.

A Possible “Third Type” of Twin

Some researchers have proposed a rare “third type” of twin. In this theory, one egg splits in two and each half is fertilized by a different sperm. This might explain why some fraternal twins look almost identical. However, this idea is still debated in the medical community and is not widely accepted as a separate category.

Who Is More Likely to Have Twins?

Twins can occur in any pregnancy, but certain factors increase the chances. In Grand Rapids and across Michigan, you may be more likely to conceive fraternal twins if:

1. Age of the Mother

  • Women in their 30s and early 40s often have higher levels of estrogen.
  • Higher estrogen can stimulate the ovaries to release more than one egg during ovulation.
  • This increases the chance of dizygotic (fraternal) twins.

2. Number of Previous Pregnancies

  • The more pregnancies a woman has had, the higher the odds of conceiving twins.
  • This is especially true for fraternal twins.

3. Family History (Heredity)

  • A woman is more likely to have fraternal twins if:
    • She is a fraternal twin
    • She has already had fraternal twins
    • She has siblings who are fraternal twins
  • These women may be “hyper-ovulators,” meaning they can release more than one egg at a time.

4. Race and Ethnicity

  • African women have the highest incidence of twins.
  • Asian women have the lowest incidence.
  • Caucasian and Hispanic women fall in between.

5. Assisted Reproductive Techniques (Fertility Treatments)

In Grand Rapids, fertility services are available through major providers such as Corewell Health (formerly Spectrum Health), Trinity Health Grand Rapids, and specialty fertility clinics. Many assisted reproductive techniques increase the chance of twins, including:

  • Fertility drugs that stimulate the ovaries to produce multiple eggs
  • In vitro fertilization (IVF), where multiple embryos may be transferred to the uterus to improve the chance of pregnancy

Both approaches can lead to multiple eggs being fertilized and implanted.

6. Weight

  • Women who are overweight may have a higher chance of conceiving twins, likely due to hormonal differences.
  • If you are planning a pregnancy in Grand Rapids, your OB/GYN at Spectrum Health, Trinity Health, Metro Health–University of Michigan Health, or Mercy Health can help you understand your personal risk and support healthy weight management.

How Pregnancy Happens: The Basics

Understanding the menstrual cycle can help explain how twins form.

  • The average menstrual cycle is about 28 days.
  • After a period, rising levels of estrogen thicken the lining of the uterus (endometrium) and trigger ovulation—the release of an egg from the ovary.
  • If sperm fertilizes the egg as it travels down the fallopian tube, it implants in the thickened uterine lining and begins to divide, forming an embryo.

With identical twins, the fertilized egg divides into two early in development.
With fraternal twins, two separate eggs are fertilized by two separate sperm during the same cycle.

Pregnancy Length and Twins

Gestation for Single Babies vs. Twins

  • A typical pregnancy with a single baby lasts about 40 weeks.
  • Pregnancies with twins—whether identical or fraternal—usually last around 38 weeks or less.
  • In general, most multiple births are delivered early and many babies are admitted to a Special Care Nursery (SCN) or Neonatal Intensive Care Unit (NICU).

In Grand Rapids, NICU services are available at major hospitals such as:

  • Helen DeVos Children’s Hospital / Corewell Health (Spectrum Health)
  • Trinity Health Grand Rapids
  • Metro Health – University of Michigan Health

Why Twins Are Often Born Early

Twins place extra demands on the mother’s body. As pregnancy progresses:

  • The uterus may not be able to supply enough nutrients and space for both babies for a full 40 weeks.
  • This can lead to preterm birth (before 37 weeks).
  • Twins are more likely to have low birth weight, which can be associated with:
    • Breathing difficulties
    • Feeding problems
    • Jaundice (yellowing of the skin and eyes)
    • Increased risk of certain developmental and medical issues

Because West Michigan winters are cold and flu season can be intense, premature babies born in Grand Rapids may be especially vulnerable to respiratory infections. Local pediatricians and NICUs are experienced in managing these seasonal risks.

Health Risks in Twin Pregnancies

Pregnant women carrying twins or other multiples have a higher risk of complications. In Grand Rapids, your obstetric team will likely schedule more frequent prenatal visits if you���re expecting twins.

Common complications include:

  • Premature birth
  • Preeclampsia (high blood pressure and organ involvement during pregnancy)
  • Preterm labor
  • Hyperemesis gravidarum (severe morning sickness)
  • Gestational diabetes
  • Anemia
  • Cholestasis of pregnancy (liver condition causing severe itching)
  • Polyhydramnios (too much amniotic fluid)
  • Bleeding during pregnancy

Because Michigan winters can limit outdoor activity and affect diet and mood, your Grand Rapids provider may pay particular attention to your blood pressure, blood sugar, nutrition, and mental health during a twin pregnancy.

If you notice symptoms like severe headaches, vision changes, intense itching, rapid swelling, or persistent vomiting, contact your Grand Rapids OB/GYN, midwife, or hospital triage line right away.

Shared Placentas and Amniotic Sacs

Knowing whether your twins share a placenta or amniotic sac is very important. This is usually determined by ultrasound at one of the local imaging centers or hospital systems in Grand Rapids.

Twins Sharing a Placenta

  • Some identical twins share a single placenta.
  • Sharing a placenta also means sharing the mother’s blood supply.
  • If blood flow is unequal, it can cause serious complications, such as twin-to-twin transfusion syndrome (TTTS).
  • Women carrying twins with a shared placenta will need more frequent antenatal check-ups and ultrasounds.

Twins Sharing an Amniotic Sac

  • If twins share the inner membrane (amniotic sac), the pregnancy is higher risk.
  • There is a chance that the twins’ umbilical cords can become tangled, which may cut off blood supply.
  • In these cases, the pregnancy is monitored very closely, often with more frequent hospital visits and monitoring.
  • Early delivery may be recommended to protect both babies.

In Grand Rapids, high-risk twin pregnancies are often managed by maternal-fetal medicine specialists at Corewell Health, Trinity Health Grand Rapids, or other regional centers.

Giving Birth to Twins in Grand Rapids

Place of Birth

For twin pregnancies, it is strongly recommended to give birth in a hospital rather than at home. This ensures access to:

  • Obstetricians and midwives experienced in multiple births
  • Operating rooms for emergency caesarean section (C-section) if needed
  • Special Care Nursery or NICU for premature or low birth weight babies

Local options include:

  • Corewell Health Butterworth Hospital / Helen DeVos Children’s Hospital
  • Trinity Health Grand Rapids
  • Metro Health – University of Michigan Health
  • Other regional maternity hospitals in West Michigan

Vaginal Birth vs. Caesarean Section

  • Many twins can be delivered vaginally, depending on:
    • The position of each baby
    • Their gestational age and size
    • The health of the mother and babies
  • A C-section may be recommended if:
    • One or both twins are in a difficult position
    • There are concerns about the placenta or umbilical cords
    • There are other medical complications

Your Grand Rapids obstetrician will discuss a birth plan with you, but plans may change quickly during labor to keep you and your babies safe.

Risks for the Babies

For twins, increased risks include:

  • Prematurity
  • Low birth weight
  • Birth complications related to:
    • Shared placenta or blood vessels
    • Limited space in the uterus (uterine restriction)

Mental Health and Stress in Twin Pregnancies

Carrying twins can be physically and emotionally demanding, especially during long Michigan winters when sunlight is limited and seasonal depression (SAD) is more common.

You may feel:

  • Overwhelmed or anxious
  • Worried about finances or childcare
  • Stressed about medical appointments and possible complications

If stress, anxiety, or low mood is affecting your daily life, talk to:

  • Your GP (primary care doctor) in Grand Rapids
  • Your OB/GYN or midwife
  • A mental health professional familiar with perinatal care

The Kent County Health Department and Grand Rapids Public Health can also connect you to local support services, parenting classes, and mental health resources.

Identical or Fraternal? (Zygosity Testing)

It can be difficult to tell whether twins are identical or fraternal at birth. Some identical twins are born with separate membranes, which can make them look like fraternal twins on ultrasound and at delivery.

How to Tell the Difference

One way to know for sure is through zygosity testing:

  • Identical twins share essentially the same genetic information.
  • Fraternal twins share, on average, about 50% of their genes, just like other siblings.

Testing can be done with:

  • A painless cheek swab to collect cells for DNA analysis
  • Blood group testing (less precise than modern DNA tests)

Your pediatrician or family doctor in Grand Rapids can help you arrange DNA testing if desired.

Why It Matters

Even if it doesn’t seem important at first, knowing whether your twins are identical can be useful for:

  • Medical history and risk: Identical twins are more likely to share the same illnesses or health conditions.
  • Organ transplantation: Identical twins are typically compatible organ donors for each other.

Local Care and Support for Parents of Twins in Grand Rapids

If you are expecting twins or already parenting multiples in Grand Rapids, you have access to a strong local healthcare network and community resources.

Medical Professionals

  • Your GP (primary care doctor)
  • Obstetrician / Maternal-Fetal Medicine Specialist
  • Midwife
  • Paediatrician / Neonatologist
  • Lactation consultants at local hospitals

Hospitals and Health Systems

  • Corewell Health (Spectrum Health) – Butterworth Hospital & Helen DeVos Children’s Hospital
  • Trinity Health Grand Rapids
  • Metro Health – University of Michigan Health
  • Mercy Health facilities in the broader West Michigan region

These hospitals offer:

  • High-risk pregnancy care
  • NICU and Special Care Nursery services
  • Childbirth and parenting classes
  • Breastfeeding support

Public Health and Community Resources

  • Kent County Health Department – prenatal support, WIC, immunizations, parenting programs
    Website: accesskent.com/Health
  • Grand Rapids Public Health and local clinics – preventive care and referrals
  • Local and national multiple birth support groups:
    • American Multiple Birth Association (AMBA) – information and peer support
      Phone: (616) 555-0400 (example local contact)

When to Seek Help

Contact your Grand Rapids healthcare provider or go to the nearest emergency department if you are pregnant with twins and experience:

  • Vaginal bleeding
  • Severe abdominal pain or cramping
  • Sudden swelling of hands, face, or feet
  • Severe headache or vision changes
  • Decreased fetal movement
  • Signs of preterm labor (regular contractions, back pain, pelvic pressure, fluid leakage)

Prompt evaluation at a local hospital can make a critical difference for you and your babies.

Expecting twins in Grand Rapids, Michigan, can be both exciting and overwhelming. With specialized maternity care at local hospitals, strong public health resources, and supportive community networks, you don’t have to navigate a multiple pregnancy alone. Regular prenatal care, awareness of potential risks, and early support—both medical and emotional—can help you and your babies thrive.