Periyava details this topic (from Deivathin Kural)::
“I said that the twice-born must perform sandhyavandana with the well-being of women and other jatis in mind. I also explained why all samskaras are not prescribed for the fourth varna. Now we must consider the question of women, why they do not have such rituals and samskaras.
Even though we perform the punyaha-vacana and namakarana of newborn girls and celebrate their first birthday, we do not conduct their caula and upanayana nor the other samskaras or vows laid down for brahmacarins. Of course, they have the marriage samskara. But in other rites like sacrifices the main part is that of the husband, though she (the wife) has to be by his side. In aupasana alone does a woman have a part in making oblations in the sacred fire…..more“
Thanks Hari for this post!