According to Hindu Mythology, during the churning of the ocean, when Lord Vishnu assumed the form of Mohini to deceive the Asuras (demons) of their share of Nectar (Ambrosia- Amrit). But Rahu and Ketu realized that the Devas (Demi-gods) were up to no good, so they sneaked into the Devas line and drank a bit of the nectar. When the Sun god and Moon god noticed this they reported it to Lord Vishnu who assumed his Vishnu Roop (form) and severed their head with his discus (Chakra). But as they had already had a bit of the nectar, they did not die and hence the severed head became Rahu (North Node) and the body became Ketu (South Node).

It is recommended that mantras and chants dedicated to Lord Vishnu (who severed the head of the demon with Sudarshan Chakra) and Lord Shiva (who drank the Halahal-blue) poison that emanated from the churning of the ocean is recited to seek blessings and good results during the eclipses.

Usually during a Chandra Grahan, a fast (Upvaas) is observed by certain communities in Hindu religion. The fast begins about 9 hours before the beginning of Chandra Grahan.

Some Precautions for the Pregnant lady :-

1. Fasting during eclipse (Grahan) will reap benefits. They should take the advice of her doctor before fasting. If you are so particular about fasting, you can fast just during the Surya Grahan period and avoid a complete fast.
2. Some traditions in Hindu religion ask pregnant women to sit or lie down on a mat containing Darbha grass or Kusha Grass. It is also advised to keep some Kusha Grass with the pregnant woman.
3. Do not eat anything that is cooked during eclipse (Grahan).
4. Pregnant Woman should stay indoors during eclipse (Grahan).
5. Pregnant Woman should not do any work during eclipse (Grahan).
6. Pregnant Woman should not do sewing during eclipse (Grahan).
7. Pregnant Woman should not be in contact with needles, pins & knives.
8. Pregnant women should not see the sun or the moon during the time of the eclipse. If they do the child born may have some kind of defect. He may be born deaf, dumb or blind.
9. Householders are forbidden from sexual intercourse on the day of the eclipse, for the same reason.
10. It is recommended to avoid sleep during the eclipse and one should engage in religious activities as then the fruits 100 times more rewarding.
The mantra that is chanted during eclipse (Grahan) by pregnant women is the Santana Gopala Mantra.

Devakisut Govind Vasudev Jagatpate Dehi Me Tanayam Krishn Tvaamaham Sharanam Gatah /