Sīmantonnayana
The popular claimThe parting of the hair is the one prenatal rite that never stopped being performed — under other names.
Three saṁskāras belong to the time before birth. Two have almost vanished. The third is performed in most Hindu families in India and the diaspora, usually without anyone calling it by its Sanskrit name.
What the texts describe
Sīmantonnayana — sīmanta, the parting of the hair; unnayana, drawing upward — is placed by Āśvalāyana in the fourth month of a first pregnancy and by Pāraskara in the sixth or eighth. The husband parts the wife's hair from the forehead backward with a porcupine quill bearing three white marks, a bunch of unripe udumbara fruit, and three blades of darbha grass, reciting verses to the effect that the child be strong and the mother safe. Then, the sūtras say, the women of the household sit with her and sing, and the text names the mood: let them speak of the auspicious.
That last instruction is the one that survived. The quill and the udumbara have mostly gone. The gathering of women around the expectant mother, the songs, the gifts, the bangles — that is the rite as it is now kept.
The living forms
In the north it is the godh bharāī, the filling of the lap: the mother-to-be is seated, her lap filled with fruit and grain and sweets by the married women of the family, and sung to. In Tamil Nadu it is the vaḷaikāppu, the bangle ceremony: bangles in odd numbers are put on her wrists by each woman present, and the sound of them is held to comfort the child. In the Telugu and Kannada country it is the sīmantham, which keeps the old name and often the parting of the hair itself. In Maharashtra, the ḍohāḷe jevaṇ, a meal for the pregnant woman's cravings. In Bengal, the sādh.
These are not corruptions of the text. They are what the text asked for — a gathering of women to speak of the auspicious — with the parts of the rite that needed a Vedic fire allowed to fall away.
Why this one lasted
Garbhādhāna needed the fire and a household ritual life; Puṁsavana carried an intent the tradition moved away from. Sīmantonnayana needed a room, some women, and a reason to gather. It also served a purpose no other rite served: it is the one moment in the whole series that is entirely about the mother. Every other saṁskāra is for the child. This one is performed on her, for her safety, and the women who keep it know that even where the name has been lost.
The porcupine quill
One detail is worth pausing on, because it shows how the sūtras think. The quill must have three white marks; the udumbara must be unripe; the darbha must be three blades. None of this is explained. The Gṛhyasūtras are manuals, not commentaries, and they record what was done without saying why. Later writers supply reasons — the porcupine for its fearlessness, the udumbara for its fruitfulness, three for the three Vedas — and those reasons are reasonable, but they are later. A reader who wants to know what the rite meant to the people who wrote it down is left with the gesture itself: the hair parted upward from the forehead, and the words that follow. That is often the honest position with these texts, and this site would rather say so than invent.
Timing
The sūtras give a month; the living forms give a season, usually the seventh month, and pick a day. Where a day is chosen by the calendar, the muhūrta treatises ask for the Moon in a nakṣatra from the gentle group and a fixed or dual rising sign, and avoid the eighth and fourteenth tithis. But the rite is not tithi-bound in the way a festival is, and most families choose by convenience. That is consistent with the texts, which give a window rather than a day.
What this page does not say
It does not say that a pregnancy without the rite is unprotected, and it does not tell anyone how to hold one. It reports a text that asked for the auspicious to be spoken over an expectant mother, and observes that the asking has been answered for two and a half thousand years under a dozen names.
Source — Ashvalayana Grihyasutra 1.14 and Paraskara Grihyasutra 1.15 on Simantonnayana; the Manusmriti on its place in the sequence; regional practice as documented in the standard ethnographic surveys of the rite
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