One issue dependent upon this topic relates to counting before nightfall, during the time known as bein hashmashot . See Shulchan Aruch Orach Chayim 489. An almost anonymous opinion is that women are exempt from sefirat ha'omer . This is the accepted halacha . This is the custom of Ashkenazic women regarding mitzvot such as shofar blowing, sukkah and lulav .
Some opinions hold that all forty-nine days comprise one large mitzvah .
Thus, one who misses a day lost the entire mitzvah and counting all other forty-eight days is worthless according to this position. Thus, reasons the Mishnah Brurah, one who will forget possibly to count one day should not even start counting with a bracha . One answer to this question returns to the observation which we mentioned at the very onset of our discussion. Sefirat ha'omer may not necessarily be dependent on a calendar date. It may be solely contingent upon the korban ha'omer .