Section Two: Maximum Period of Pregnancy according to Physicians
As already discussed, physicians and jurists agree as to the minimum period of pregnancy (six months) and the frequent period of pregnancy (nine months) but they differ as to the maximum period of pregnancy. Modern medicine is of the opinion that the maximum period of pregnancy is ten months. In rare and exceptional cases, this period may reach eleven months (330 days). It is not known that a placenta can provide the fetus with the ingredients of life for this period.  The expert and specialist physicians who participated in the 11th session of the Islamic Fiqh Academy of the Muslim World League in Makkah opined according to a document signed by all of them that it is impossible for the pregnancy to continue more than one year (more than 365 days).  This is the opinion adopted by the laws of personal affairs in some Muslim countries. 
Dr. Najm `Abdullāh `Abdul Wāḥid writes, "There is no doubt that the period of pregnancy naturally extends to nine months; that is forty weeks and medical statistics indicate that 60% of women give birth within this period, that 25% of women give birth within the forty-second week, that about 12% of women give birth within the forty-third week and that a low percentage of women (3%) give birth in the forty-fourth week, namely within a maximum period of ten months only." 
Dr. Muḥammad `Alī Al-Bār writes, "The normal period of pregnancy is 280 days calculated from the start of the last period. As pregnancy usually takes place on about day 14 from the start of menstruation, the actual period of pregnancy is then 280-14=266 days. Therefore, advancement or delay of birth by two weeks from the calculated period is normal. The date of birth may also delay by one month even if the calculation is accurate." 
He adds, "The maximum period of pregnancy according to physicians does not exceed one month after the expected date of delivery; otherwise, the fetus would die in the womb. They consider any time more than this as miscalculation." 
Dr. Najīb Mahfoudh, an obstetrician, writes, "The complete period of pregnancy is ten lunar months, i.e. two hundred and eighty days, or nine Gregorian months and seven days calculated from the first day of the last menstruation period before pregnancy." 
Dr. Ahmad Kan'ān writes, "Physicians estimate the average period of pregnancy at forty weeks (280 days) which means that the actual period of pregnancy is 280 – 14 = 266 days, namely about nine lunar months. A woman may miscalculate the age of her pregnancy if her period is irregular, a miscalculation that may reach two weeks by increase or decrease."  He adds, "Physicians are of the opinion that pregnancy does not delay from the normal date except by a short period often not more than two or three weeks and that births that take place between weeks 39 and 41 enjoy the best fetal safety. However, if they delay beyond week 42, fetal safety is jeopardized. In rare cases a fetus survives if it remains in the womb for 45 weeks. To accommodate for these rare and exceptional cases, this period is extended by two further weeks to become 230 days. It is not known that a placenta could provide the fetus with the ingredients of life for this period." 
Physicians are of the opinion that it is impossible for the fetus to continue growing inside the womb for several years.
"Obstetricians and gynaecologists in the present time have reported millions of cases but none of them extended to one year, let alone several years." 
However, the fetus may remain dead in the womb for a long period. It may become calcified and then ejected by the womb as a whole or at intervals. 
Therefore, physicians term the events of prolonged periods of pregnancy mentioned by jurists, assuming they were true, as false pregnancy (pseudo pregnancy). A woman may remain falsely believing to be pregnant for one year or more because she has the symptoms of pregnancy like the cease of the menstruation, vomiting, pains and big abdomen. She may have a real pregnancy after that and thus she thinks to have pregnancy from the time she falsely believed to be so. In modern times, it is easy to diagnose such a case by ultrasound which was not available in old days.
Topic Four: Effect of Agreement and Difference between Jurists and Physicians as to the Minimum and Maximum periods of Pregnancy and the Inheritance of the Fetus
Two conditions have already been mentioned for the fetus to be entitled to inheritance ; one of them is the confirmed existence of the fetus in the womb at the time of the death of the heritor even if it is a semen. It is also already stated  that jurists and physicians are in agreement as to the minimum period of pregnancy (six months) but differed as to the maximum period of pregnancy.
The effect of such agreement and difference as to the inheritance of the fetus is clear from knowing the methods by which the existence of the fetus in the womb at the time of the death of the heritor can be confirmed.  Here are these methods:
The First Method:
The mother may deliver after the lapse of less than six months from the death of the heritor and the baby may thrive, in which case the baby is given his share of the estate of the heritor whether his mother is remarried or not. In order that it is confirmed that he was in the womb at the time of the death of the heritor because he did not stay in his mother's womb for six months, the fetus being born alive is a clear cut proof that he was in his mother's womb at the time of the death of his heritor; otherwise he would not have been born with a stable life. This ruling is based on the minimum period of pregnancy (six months) which is a point of agreement between medicine and jurisprudence.
The Second Method:
The mother may deliver after the lapse of six months or more from the time of the death of the heritor up to the maximum period of pregnancy. In this case, the baby is given his share of the estate of the heritor if the mother is not remarried during this period. It is more likely that the fetus was in the womb at the time of the death of the heritor unless the period of pregnancy extends beyond the maximum period determined by jurists. However, if the maximum period of pregnancy is exceeded or if the mother remarries during the period of pregnancy, the baby would not be given any share from the estate of the heritor for it is probable that the pregnancy resulted from the new marriage after the death of the heritor. In this case, the condition of inheritance is not met. Through the above discussion  of the opinions of jurists and physicians with regard to the maximum period of pregnancy, it becomes clear that physicians and jurists differ as to this issue even if the opinion of jurists who do not fix a specific maximum period of pregnancy.
However, the physicians are of the opinion that pregnancy does not exceed a specific period (ten months or perhaps eleven months) which is equal to 330 days for rare and exceptional cases usually resulting from miscalculation. They state that it is not known that a placenta could provide the fetus with the ingredients of life for this period. 
By comparing the proofs given by jurists and physicians, I am of the opinion that the opinion of reliable specialist physicians should be accepted as the rule because they give a scientific proof based on the latest discoveries of medicine while the proofs given by jurists are based on events that might be true or false. Therefore, Ibn Ḥazm contends that they were false news told by unreliable and unknown people.  Assuming that this news is true, they should be classified as miscalculations according to physicians who term them as false pregnancy. This is supported by the statements of several judges in the Kingdom of Saudi Arabia who stated that the cases of inheritance considered by them have never included a case of pregnancy more than nine months. Based on the opinion of physicians about the maximum period of pregnancy (ten months) or eleven months as a precautionary term, the pregnant woman who may deliver a live baby after six months of pregnancy or more from the death of the heritor up to the maximum period of pregnancy without remarrying, the baby is given his share from the estate of the heritor because he was in the womb at the death of the heritor. However, if she exceeds the maximum period of pregnancy (eleven months), the baby is not entitled to any share because he was not in the womb at the time of the death of the heritor unless the other heirs accept him as one of them.
The Third Method:
If a medical report is issued by the pertinent authority confirming the existence of the live fetus in the womb at the time of the death of the heritor by using advanced medical systems which are available these days like laboratory tests, ultrasound, x-ray and fetal ECG's.  This method dispenses with the other methods for confirming the existence of the living fetus in the womb at the time of the death of the heritor which entitles the baby to his share from the estate of the heritor. This method can also be applied to realize the second condition of inheritance, namely to confirm the life of the baby when delivered.
Jurists accept the opinions of physicians and other specialists when needed. In case of difference as to the injuries which are only known to physicians, Ibn Qudāmah writes, "The apparent meaning of Al-Khuraqī's statement is that if two physicians are available, a single one is not sufficient because these issues are the specialty of men for which no one testimony is acceptable as the case with other rights. However, if no two specialists are available, a single one is sufficient because it is a matter the knowledge of which belongs to specialists. This is similar to the case of defects under clothes for which the testimony of one woman is sufficient. Therefore, the testimony of one man, for a greater reason, is more acceptable." 
All praise belongs to Allāh and peace and blessings be upon the last Prophet. Through the above discussions, the following conclusions can be reached:
1. The Islamic Sharī'ah gives great importance to inheritance and giving everyone his due right.
2. The Islamic Sharī'ah gives due attention to the fetus to the extent that it gives him the right to inherit and urges protecting it until his condition becomes clear after birth.
3. For the fetus to inherit, it should be verified to be present in the uterine at the time of the death of the heritor and to be of a stable vitality when he is born.
4. According to Jurists, the minimum period of pregnancy is six months so that when the baby is born it may have a stable life.
5. According to medical literature, the minimum period of pregnancy is six months. Medical evidence affirms that the baby born before completing six months of pregnancy cannot live a stable life.
6. According to Jurists, the maximum period of pregnancy is not limited to a specific time according to the preponderant juristic opinion although some jurists limit it to nine months, some others to one year, two years, three years, four years, five years, six years or even seven years.
7. According to medical literature, the maximum period of gestation is ten months and perhaps eleven months (330 days) in rare cases. Any extra period is the result of miscalculation.
8. Medical literature is of the opinion that it is impossible for the fetus to remain alive in the uterine for several years. They view jurists' opinions with regard to the excessive period of pregnancy as meaning that the fetus remains in the uterine dead until calcified or as indicating false pregnancy.
9. If the woman gives birth to a viable baby within less than six months from the death of the heritor, the baby has the right to inheritance as the condition of inheritance is established.
10. If the woman gives birth to a viable baby within six months or more from the time of the death of the heritor, the baby is entitled to inheritance unless his mother has been a wife for another husband after the death of her earlier husband, or she
has not had suspected sexual intercourse or committed adultery as the condition of inheritance is established.
11. If the gestation period exceeds eleven months (330 days) from the time of the death of the heritor, the baby has no right to inheritance because he was not present in the uterine at the time of the death of the heritor but a product of a more recent sexual intercourse.
12. I recommend that judges should not suffice with evidence of actual pregnancy at the time of documenting heirs. Rather, they should request the claimant woman to submit a medical report on her condition to confirm her claim and to rule out false pregnancy.
 Period of Pregnancy, Islamic Jurisprudence Academy Journal, p. 254, Issue No. 4, 2nd year, 1410 AH.
 Islamic Jurisprudence Academy Journal, p. 254, Issue No. 4, 1410 AH.
 The Fetus and Related Rulings in Islamic Jurisprudence, p. 151 and The Estate and Inheritance in islam, Muhammad Mousā, p. 343.
 Period of Pregnancy, Islamic Jurisprudence Academy Journal, p. 251, Issue No. 4, 2nd year, 1410 AH.
 Human Creation between Medicine and the Qur'ān, p. 452.
 Ibid, p. 452.
 The Fetus and Related Rulings in Islamic Jurisprudence, p. 151.
 Medical Juristic Encyclopedia, p. 374.
 Medical Juristic Encyclopedia, pp. 375-376.
 Ibid, p. 377.
 Human Creation between Medicine and the Qur'an, p. 453.
 Medical Juristic Encyclopedia, pp. 336; Human Creation between Medicine and the Qur'an, p. 453; Period of Pregnancy, Islamic Jurisprudence Academy Journal, p. 252, and Rulings on Pregnant Women and Fetuses, p. 119.
 Section Four of Topic One.
 Section Two.
 Al-Adhb Al-Fā'idh, 2/91; At-Tahqīqāt Al-Mardhiyyah, p. 218; Al-Farā'idh, p. 142; Ruling of Inheritance in the Islamic Sharī'ah, p. 180 and Summary of the Doctrine of Inheritance, p. 444.
 Topic Three.
 Section Two of Topic Three.
 Section One of Topic Three.
 Events Related to Women with Regard to Worships and Family Affairs, Dr. Muna Ar-Rājih, a Ph.D. Dissertation, Imam Muhammad University, p. 910.
 Al-Mughnī, 9/270 and Tabsirat Al-Ḥukkām by Ibn Farhūn, 2/81.