Eugenic indications are cited of
there is a “substantial risk of the child being born with serious physical and
mental abnormalities so as to be handicapped in life.” This heading includes conditions such as structural
abnormalities (anencephaly), chromosomal disorders (Down's), genetic diseases
(hemophilia), exposure to teratogenic drugs, radiation, and rubella. There is
no mention of OH in the list of indication for MTP
However,
the definition of “serious mental abnormalities so as to be handicapped in
life” is a qualitative one. In the present era of patient-centered care, the
mother's opinion about possible psychoneurological impact on
unborn offspring should be taken into account.
DM:--To
take an example from obstetrics, the option of MTP is offered to patients with
uncontrolled diabetes presenting with an unplanned conception, but there is no definitive HbA1c cut-off at
which to make MTP mandatory. The choice is usually made by a process of shared
decision making, keeping the patient's individual characteristics in mind.
In later pregnancy, the triple marker test can be applied to assess the risk of
Down's syndrome, trisomy 18, and neural tube defects. However, there is no definite
value at which to enforce an MTP: the results can at best be considered
suggestive of the fetal risk. Similarly, in pregnancy complicated by OH, the
decision to continue or terminate pregnancy will vary from case to case based
on multiple factors
Summary
Keeping
the above discussion in mind, we suggest the following algorithm of management:
·
Patients with SCH, at any gestation:
Treat as per guidelines, with l-thyroxine. Do
not consider MTP.
·
·
Patients with OH, beyond 20 weeks
gestation: Treat as per guidelines, with l-thyroxine. Do not consider MTP.
·
Patient with OH, below 20 weeks
gestation: Treat as per guidelines, with l-thyroxine. If conception has
occurred without difficulty, and OH is “severe," take a final decision
after discussing all aspects with the patient. MTP cannot be recommended at
present unless there is a request from the patient.
Conclusion
Maternal
hypothyroidism is relatively common and may not be diagnosed (and therefore not
treated) during pregnancy. This may even remain undiagnosed for several months
after delivery. Currently it seems unclear as to how detrimental this may be
for the development of the neonate. The consequences of maternal hypothyroidism
on the fetus or neonate are probably the result of interplay of several factors
acting, such as decreased availability of maternal thyroid hormones at crucial
times in fetal brain development, obstetric events associated with maternal
hypothyroidism, and possibly prolonged concealed maternal hypothyroidism during
pregnancy. Ethically important but debatable issue is whether clinicians should
recommend terminating pregnancy when severe hypothyroidism is diagnosed late in
gestation. Present consensus among obstetric care providers and
endocrinologists is against recommending abortion, but despite the
administration of thyroxine, future parents cannot be fully reassured about
potential brain damage as a result of longstanding and severe intrauterine
undiagnosed hypothyroidism. Keeping in view the nature of the condition, it seems highly unlikely that any
randomized clinical trial will ever be done to assess the TSH level cut-off at
which MTP must be the advised.
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