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Often viewed as a novelty or miracle, a multifetal pregnancy that includes twins, triplets, and higher-order multiples are discussed under the heading of ‘complications of pregnancy’ in medical literature. These pregnancies often present a challenge in management for the obstetrician and can be a potentially perilous journey for the mother and her unborn children.
Pregnant with Twins
As you know there are identical twins which look exactly the same and are always of the same sex and there are fraternal twins who do not exactly resemble each other and could be a boy and a girl. What are the chances of conceiving twins and what factors determine this?
The chance that you might conceive twins primarily depends on which country you belong to, which race, what is your age and did you undergo any infertility treatment. Other factors include use of oral contraceptives, heredity and nutritional factors.
Fraternal or dizygotic twins (the more commonly seen types) result from fertilisation of two separate eggs.
Less common types, identical or monozygotic twins arise from a single fertilized egg that divides into two. A zygote normally grows into an amnion that will form the amniotic membrane or the water bag, the chorion that will form the placenta and the embryo that will grow into a foetus. Depending on when a monozygote divides there are types of monozygotic twins:
- If zygotes divide within the first 72 hours after fertilisation, two embryos, two amnions, and two chorions develop, and a diamnionic, dichorionic twin pregnancy evolves. Two distinct placentas or a single fused placenta may develop.
- If division occurs between the fourth and eighth day, a diamnionic, monochorionic twin pregnancy results.
- By approximately 8 days after fertilisation, the chorion and the amnion have already differentiated, and division results in two embryos within a common amnionic sac, that is, a monoamnionic, monochorionic twin pregnancy.
- Conjoined twins result if twinning is initiated 13 days or more after fertilisation; this is extremely rare.
Early Signs and Symptoms of a Twin Pregnancy
Symptoms for twins during pregnancy vary from mother to mother, but most mothers report exaggerated pregnancy symptoms from a very early stage.
Higher HCG Levels
Blood and urine levels of β-hCG are generally higher with twins compared with singletons. This is the one of the Early signs of twin pregnancy seen in the first 2 weeks. The conformation by a transvaginal ultrasound can only be done by 8th week at the earliest. HCG is the hormone which is responsible for the implantation and development of the zygote, and is understandably higher when twins are concieved
Extreme Morning Sickness
Also called as hyperemesis gravidarum, this begins in the first trimester, and is associated with higher serum β-hCG levels. Women with multifetal gestation often have nausea and vomiting in excess of women with a singleton pregnancy. The morning sickness may also last for longer as opposed to mothers carrying one baby who normally see the symptoms fade in the beginning of the second trimester
Women carrying twins may be initially totally asymptomatic or may have normal signs and symptoms of pregnancy including breast tenderness, fatigue, nausea, vomiting and cramping. lt is however possible that these symptoms are exaggerated. But to feel what is exaggerated you need to first feel what is normal. So such intuition- based feelings are more common in a a mother who has experienced singleton pregnancy earlier.
Other Twin Pregnancy Symptoms
The symptoms of twin pregnancy are not very different for those of a single pregnancy. as discussed earlier, these symptoms may be on a larger scale.
1. Excess Weight Gain – Weight gain more than singleton pregnancy is obvious as there is one more life growing in your womb. The approximate weight in excess is 9 Kgs.
2. Uterus Larger Than Date – Twin gestation may be suspected if the abdominal size is greater than expected compared to menstrual dates. The uterus and its non- foetal contents may achieve a volume of 10 L or more and the fundal height approximately 5 cm greater than expected for singletons of the same foetal age.
3. High Blood Pressure – Women carrying twins also have a typical pattern of blood pressure change. In early pregnancy, the diastolic blood pressure (the denominator) in women with twins is lower than that with singleton pregnancies but generally increases to a greater degree (2.5 times) at term. Also there is increased incidence of pregnancy induced hypertension (PIH) and its related complications.
4. High AFP (Alpha-fetoprotein) Test Result – MSAFP (maternal serum alpha-fetoprotein), similar to β-hCG levels increase in the second trimester but compared to singleton pregnancy its level is variable.
5. Extreme Fatigue – A larger uterus, more weight and extra nutrition and energy required to sustain a twin pregnancy leads to comparatively higher fatigue.
6. Early Foetal Movement – While there is some debate on the authenticity of this symptom, most mothers report experiencing the foetal movements, or quickening earlier than in a singleton pregnancy.
7. Frequent Foetal Movement – This is a very variable symptom as it is reported one by some mothers carrying twins.
8. Breathlessness – Especially with monozygotic twins, excessive amounts of amnionic fluid may rapidly accumulate in addition to the larger uterus occupying more space in the abdomen. The maternal abdominal organs and lungs can be appreciably compressed and displaced by the expanding uterus causing breathlessness. While this is a common symptom of pregnancy in general, a woman pregnant with twins may be more prone to breathlessness,
9. Digestion Issues – These are common with singleton pregnancies too, and may add to your discomfort. In twin pregnancy, as the uterus is larger, the issues faced due to pressure on the digestive system are more too.
10. Back Pain – Carrying a larger and heavier uterus while trying to maintain the back posture definitely stresses the back causing pain.
11. Insomnia – Multiple factors internal and external can deprive you of a good night’s sleep. The discomfort, the improper position, pain, increased breathlessness on lying down, and various psycho-social factors are responsible for poor sleep.
12. Depression- The joy of having twins in some cases gets overruled by the physical, mental and social stress. A twin pregnancy is associated with lot more foetal and maternal complications. One third of the mothers expecting twins suffer depression as per a study.
13. Extreme Breast Tenderness – It is an early symptom seen commonly from week 4-week 7. It may last longer. You can also have increased pigmentation of the areola, around the nipple.
14. Frequent Urination – During early pregnancy increased blood flow to the kidney increases the urine output. In the later stages of pregnancy, there is an increase in the pressure over the bladder by the larger uterus. This impairs the complete filling of the bladder and hence the increase in urination.
15. Cramping – As the embryo implants on the inner lining, there will be some cramping as during menses. In twins with two embryos implanting the discomfort is slightly more.
16. Water Retention –There is increase in the water retention secondary to the effect of oestrogen
17. Fast Heartbeat – Increase in the heart beat is secondary to changes in the blood pressure and blood volume. It is maximum in last trimester.
How to confirm your Twin Pregnancy?
1. Clinical Evaluation
Careful examination with a foetal stethoscope can identify foetal heartbeats in twins as early as 18 to 20 weeks. Palpating (feeling by pressing gently over the abdomen) two foetal heads strongly supports a twin diagnosis.
2. Ultrasound Confirmation
Ultrasonography is the most reliable method for diagnosis of twin pregnancy. The optimal time for diagnosis is in the first trimester or early second trimester. If two separate placentas are seen, dichorionic gestation is diagnosed. It is important to know the chorionicity as soon as possible during pregnancy because it can affect future management decisions.
3. Doppler Heartbeat Count
Late in the first trimester, foetal heartbeat may be detected with Doppler ultrasonography. It is then possible to identify two foetal heartbeats if their rates are clearly distinct from each other and from that of the mother.
4. Magnetic Resonance Imaging
In rare circumstances when the diagnosis is doubtful on ultrasonography, a MRI may aid the diagnosis. However, an MRI uses a magnetic field, and pulses of radio frequency and there is some apprehension that it my not be advisable in pregnancy. The Journal of The American Medical Association has stated that it is safe to have an MRI done in the first trimester, but it is advisable to consult your doctor about any possible side-effects before opting for it.
If you have just discovered that you are carrying twins, do make sure to take extra care of yourself and enjoy your double dosage of joy!